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Alarms and security related schematics

Electronic door codelock (PIC16F84)
Ultrasonic remote control & alarm system
Digital entry lock
Proximity switch
Toxic Gas Detector
Door knob alarm (PDF)
Water seepage alarm (PDF)
Micro-power over temperature alarm (PDF)
Personal silent alarm system
Active IR motion detector
A Basic RF Transmitter for PIR Sensors
PIR motion detector
Simple alarm system
Automatic door opener using PIC12C508
Home security project
5 Zone alarm circuit
Miniature loop alarm
Novel Buzzer
Gate alarm circuit
Modular Burglar Alarm
Motorcycle alarm
Enhanced 5 Digit Alarm Keypad
Enhanced 4 Digit Alarm Keypad
RF Alarm
Single Zone Alarm
Water Activated Alarm
Water level alarm
Perimeter monitor
Digital combination lock
Alarm control keypad
Almost Ultrasonic Motion Sensor
Touch activated alarm system
Combination Lock (PIC16F84)
Low power RFID transponder


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Audio power amplifier schematics
Two transistor audio amplifier
Personal stereo audio amp
Headphone amplifier
1.5W Audio amplifier
Low-level audio amp
10W amplifier
80W amplifier
LM383 12V Amplifier
100W Amplifier
18W Audio amplifier
25W MOSFET amplifier
Headphone amplifier
Portable headphone amplifier
2W amplifier
4W amplifier
8 watt audio amp
20W Amplifier
50W Amplifier
100W Audio amplifier
100W RMS Amplifier
2-Channel Power Amplifier
Push-Pull Class A Amp using type 5687 dual triodes
Push-Pull Class A 2A3 Stereo Amp
Single Ended Class A2 SV811-10 Stereo Amp
Audio amplifier output relay delay
Spatial Distortion Reduction Headphone Amp
HeadBanger Headphone Amp
2W Amplifier
TDA2030 8 Watt amplifier
Headphone distribution amp
Headphone monitor amp
50W audio power amplifier
Bi-Directional 2.4 GHz One Watt Amplifier
Bi-Directional 900Mhz One Watt Amplifier
20 Watt GaAaFET Power on 2.3 GHz
1 Watt 2.3 GHz RF Amplifier Using a MRF2001
2.3 GHz Power Amplifiers
2304 and 3456 MHz Power Amplifiers
High quality exponential VCA
16 Watt amplifier
8 Watt amplifier
Power amp schematic (PDF)
20 Watt Class-A Power Amplifier
El-Cheapo - A Really Simple Power Amplifier
Single Chip 50 Watt / 8 Ohm Power Amplifier
Hi-Fi Headphone Amplifier
100W Guitar Amplifier
Death of Zen (DoZ) - A New Class-A Power Amp
Soft-Start Circuit For Power Amps
Thermo-Fan To Keep Your Amp Cool
Audio Amp Output Power Limiter
55W (Originally 75W) Power Amplifier
300W Subwoofer Power Amplifier
20 Watt / Channel Stereo Power Amplifier
Mini bench amplifier (LM386)
12 Watt Valve Guitar Amp

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Audio preamp circuits
Microphone amplifier
RIAA phono amplifier
Low impedance microphone amplifier
Dynamic microphone preamplifier
Phono preamp
Masthead preamp
Preamplifier for microphone or guitar use
Simple microphone preamplifier
Tube microphone preamp
Simple Stereo Electret Microphone Preamplifier
Simple Stereo Electret Microphone Preamplifier
Phono Preamp
Simple microphone preamplifier
ECM Mic preamp
Hi Fi preamp
Balanced microphone preamp
Audio preamp
Electret mic amplifier
Audio preamplifier
Vacuum Tube Microphone Preamp
FET Preamp Cable
Audio preamp

Automative, car and motorcycle schematics
Electronic auto stethoscope
Turn signal alarm
Motorcycle turn-signal system
Cigarette lighter 9V adaptor
Analog Tachometer for Gasoline Engines
Headlight On reminder with Light
Adaptive Windscreen Wiper Control
Car clock
Car message display
Car interval wiper
Safety indicator light
Speed limit alert
Grand Cherokee Off-Highway Lights
Engine control unit schematics
Portable CD Player Adapter For Car
Car battery charger
Wireless Auto Tachometer
Alternator Signal Detector
Automotive alarm system
Road ice alarm
Automotive Anti-Lock Brake Control Driver
Headlight reminder
Breath Alcohol Tester controlling a car ignition system
Simple car battery charger
Parking sonar
Fuel injector pulse width monitor
BMW R Series Motorcycle Regulator Schematic
80188XL Engine Tachometer
Integrate Fuel Pump Wire Security Cut Off with a Turbo Timer
Simple Car Preamplifier and Artificial Earth
FCD (Fuel Cut Defencer)
Interface between GM's 5 Volt 8192 baud ALDL data stream and a PC serial port
5301 wideband fuel mixture display
Wide Band Fuel Mixture Display
3rd brake light
12V to 9V car coverter
Car Nicad charger
Combination lock for car liftgate
BMW motorcycle side stand protection mod

Data acquisition and data logging schematics
Air flow detector
Air flow detector
Strain gauge sensor
Digital Water Wave/Tide/Level Meter (PIC16F876)
Self made data-logger V2.5 (second edition)
Analog input section based on AD9220
uModem 4+4/8 channel A/D board
ADXL202 accelerometer to CV output
Light direction sensor
12-Bit ADC interface
Digital thermometer
Universal flight controllers / datalogger
Rain detector
Home Brew Compass Sensor
Using 555 Timer as an A/D converter
ADC0804LCN 8-bit A/D converter
Web-based thermometer project
Low Flow-Rate Thermal Flowmeter
Geiger counter
Differential Capacitance Measurement for Tilt Meter
Honey Bee counter (PDF)
Capacitance type liquid level measurement (PDF)
Thermostat node schematic
Digital PC Oscilloscope
Ultrasonic Range & Imager
Precision Digital Altimeter
Digital compass schematic
Temperature datalogger
Serial Port A/D-converter
Centronics port D/A converters and low-pass filter
LCD Thermometer
Acceleration monitor using Analog Devices ADXL202
Optical sensor using PIC12C508
Wireless Liquid Level Sensing for Restaurant Applications
Accelerometer Schematic
Pressure Sensor-Based Altimeter Circuit
Ultrasonic range finder circuit
1-wire barometer
Water-level sensor
Addressable ADC
Electronic altimeter using PIC16F877
Wireless weater station

Filter schematics
Galaxy Noise Filter
Low-pass active filter
Filter Circuit for the Earthworm Seismic Data Acquisition System
Active 2nd Order Filters
RC Notch Filter (Twin T)
Multiple Feedback Bandpass Filter
CW filters
Self-tune filter
SSB AF filter
Helical Resonator Notch Filter
3KHz low-pass filter plus audio amp (PDF)
Active bandpass filters
Bandpass filters
Butterworth filters
Narrow band audio bandpass filter
Inversal notch and bandpass filter
DC Accurate, Active RC Lowpass Filter
Chebyshev Bandpass Filter
Bandpass filters
Chebyshev / Butterworth filters
Biquad Active Bandpass Filter Schematic
"A" Weighting Filter For Audio Measurements
Multiple Feedback Bandpass Filter
Digital signal processor (DSP) for radio communications
29.85 MHZ bandpass filter schematic
29.85 MHZ notch filter schematic
LC filter design

Games and fun stuff (schematics)
Visor cradle serial interface
Electronic coin tosser
Electronic craps game
First response monitor
VCR ping pong game
Video ping pong game
MBC5/CPLD for the GameBoy
GameBoy Camera Parallel Port Interface
Mobile robot (PDF)
PSX controler to PC MIDI converter
Dreamcast PC serial adapter
GameBoy Cart Programmer
Memory game
32 Kb x 8 emulator for the GameBoy
Project: NES to Atari 2600 controller interface
Battery Meter for Pinball Machines
SRX1 (Stephane's Robotic eXperiment 1)
Pine Racecar Victory Judge
Interfacing Sony control stick to Empeg
Electronic Nicad glow plug driver
April Fools LEDs
Pinewood Derby logic
Quiz Master
GameBoy Schematic
GameBoy LCD schematic
GameBoy Power & Cartridge schematic
GameBoy ROM+RAM+MBC1 Cart Schematic
GameBoy MBC1 circuit equivalent
Super GameBoy schematic
Quiz show indicator
Dreamcast interface
Bingo!!! (on your tv)
Slot car TV cronograph
Furby reverse-engineered circuit
Sanyo 20EZ monitor Arcade Game (300k ZIP)
Burger Time Arcade Game (500k ZIP)
Dig Dug Arcade Game (800k ZIP)
Frogger Arcade Game (500k ZIP)
Galaga Arcade Game (542k ZIP)
Gyrus Arcade Game (800k ZIP)
Junior Pacman Arcade Game (400k)
Ladybug Arcade Game (335k ZIP)
Mappy Arcade Game (470k ZIP)
Moon Cresta Arcade Game (300k ZIP)
Mr.Do Arcade Game (554k ZIP)
PacLand Arcade Game (316k ZIP)
Pengo Arcade Game (313k ZIP)
Q*Bert Arcade Game (600k ZIP)
Qix Arcade Game (476k ZIP)
Scramble Arcade Game (600k ZIP)
Time Pilot'84 Arcade Game (870k ZIP)
Xevious Arcade Game (450k ZIP)
Magic Wand Conjuring Trick
Quiz game circuit
E.S.P. Conjuring Trick
Video game system using PIC18F252 (direct video generation)
Video game system using SX28 (direct video generation)
DIT shutterglasses controller
Tic-tac-toe game using PIC16F628
Archery timer
PIC micro Tetris game
Magic lamp, IR remote control jammer and other fun circuits (PDF)
Lego Mindstorms Double Rotation Sensor

Infrared based schematics
IR detector
Infrared body heat detector
Stereo IR audio receiver
General purpose IR receiver
Wireless IR headphone transmitter
Wireless IR headphone receiver
Infrared remote control shutter release system
Infrared transmitter for locomotives
Infrared gate for door
Infrared circuits for remote control
Serial port controller infrared transmitter (PIC16F628)
IR Receiver (Amplitude Modulated IR)
IR Transmitter for Audio (Amplitude Modulated IR)
Digibox interface
IR remote control
Long Range Infrared Remote
iRDA to TTL interface
40KHz light receiver (PDF)
40KHz TV-VCR repeater (PDF)
Micro based PIR to IR remote converter
IR-related ASCII Schematics V1.00
Infrared remote transponder
Build an Infrared night scope
Decoding IR Remote Controls
IR detector
PC IR Remote Control Hardware
PC IR Remote Control
An Ambient-Light-Ignoring Infrared Active Motion Detector
Infrared Transmitter and Receiver schematic diagrams
Pyroelectric Infrared Sensor
Minimal Infrared transmitter for PC
Simple IR transmitter circuit
Simple infra-red detector
AVR (AT90S2313) serial port infrared receiver
Infra Red Switch
IR remote control extender
IR Remote Control Extender Circuit (Mark 2)
IR Remote Control Extender Circuit (Mark 3)
IR Link
IR remote control tester
40khz IR Tester
555 timer 40khz IR Oscillator
IR detector / emitter
Fire-Stick infrared remote control
Simple infrared remote control
Infrared / Ultrasonic beacon
Implementing Infrared Object Detection
IR detector for robotics
Computerized Infrared Remote

Laser related power supplies and data transmission
Light beam receiver for laser pistols
12V supply for He-Ne laser
Laser diode transmitter
Laser power supply
Laser transmitter/receiver
Laser harp
Laser Telephone Receiver Circuit
Fiber Optic Voice Communications
Efficient Laser Supply
20MHz VCSEL 3mW laser test circuit (PDF)
10MHz to 20MHz laser light detector (PDF)
Micro-power 40KHz burst laser diode driver (PDF)
40KHz laser burst detector (PDF)
Modulated laser diode tester (PDF)
Ar/Kr Ion Laser Power Supply
Laser diode power supply circuits
RS-232 Laser Transceiver
HeNe laser power supply
OPT201 Laser receiver
OPT301 Laser receiver
Laser transmitter schematics
Diode Laser Power Supplies
Laser bug circuit
RS-232 Laser Transceiver
Experimental laser data link
Ar/Kr Ion Laser Power Supply Design
Simple laser communicator

LED related schematics
Big 7-segment LED display board with SPI interface
LED Flasher
LED pulser with audible output
IR Illuminator
Flashing Christmas LED display
ICL7660 LED flasher
LM3909 replacement using discrete components
Color fade
LEDs shimmer randomly as though on fire
LED power supplies for AA cells
1.5 Volt LED Flashers
AC Line Powered LEDs
Astable Multivibrator
9 Second Digital Readout Timer
9 Second LED Relay Timer
16 Stage Bi-Directional LED Sequencer, other sequencer and flaser circuits
10 Stage LED Sequencer
28 LED Clock Timer
Fading Red Eyes
Two Transistor LED Flasher
16 Stage Bi-Directional LED Sequencer
Expandable 16 Stage LED Sequencer
LED Photo Sensor Circuit
LED chaser
7 Segment LED Counter
7 by 10 LED Moving Sign ( 27C512 EPROM)
Sequencial LED Flasher with Reversable Direction
Tri Color LED Controller with Serial Interface
1.5V LED flasher B (PDF)
Low current LED flasher (PDF)
1.5V LED flasher A (PDF)
Flashing LED advertising badge (PDF)
Flashing LED advertising badge (PDF)
Pulsed LED test circuit (PDF)
Low battery voltage flasher (PDF)
Adjustable flashing LED
PWM white LED drivers
Heart of LEDs
Christmas Star
Christmas tree
LED Counter
PIC16F84 LED chaser
PIC16F84 LED signboard
PIC16F84 LED signboard 2
White LED circuits
Assorted LED circuits
LED Mood Light
LED Audio VU Meter
Robot Beacon rotating light using PIC12C508
LM3909 LED flasher
Animated LED signboard (PIC16C84)
Picxie 2 - 8x8 Animated LED Signboard

Lighting schematics
Garden light switch
DMX lighting and special effects
Microcontroller Multichannel Light Dimmer
Digital timer light switch
Hand clap lamp control
Radio controlled light switch
Disco style Strobe Light
Varying Brightness AC Lamp
12 Volt Lamp Dimmer
120VAC Lamp Chaser Using Solid State Relays
Flashing Neons (NE-51 / NE-2)
Sequencing Neons (NE-51 / NE-2)
Touch Activated Lamp
220V Flashing lights
Coutesy lamp
Bedside lamp timer
TRIAC light dimmer
12VDC Fluorescent Lamp Driver
Strobe light
Adjustable Strobe Light
RHINO8 EL Sequencer
Light Sequenced Candelabra
Light timer
5W Fluorescent light intensity modulator (PDF)
1W Fluorescent lamp night light (PDF)
Low-voltage light dimmer
Light chaser
4-channel dimmer rack
PIC16F873 light controller
Disco light controller
Neon desklamp
Electronic night light
Neon lamp dimmer
LED Mood Light
LX-800 Lighting system
Xenon Strobe Light
Lamp flasher/dimmer

Medical and health related schematics
Snore alarm electronic device
Heartbeat transducer
ECG Amplifier
EKG/EEG circuit
Radiation Dosage-Rate Meter
Heartbeat monitor
Cranial Electrotherapy Stimulator
Automated crib lights
Jogging timer
Tan timer
Muscular Bio-stimulator
Simple lie detector
EEG preamp, anti alias filter and isolation circuit
Self Contained Electromyograph (EMG)
Cardiac monitor
Galvanic Skin Response (GSR) Schematic
Brain-Wave Machine
Lie detector
Simple lie detector
ECG project page
The ESP SIM (Sound Impairment Monitor)
Respiration system

Microcontroller based schematics
PIC based packet radio encoder (PDF)
RS485-Version of the SAB80C535-Microcontrollerboard
PC IR receiver based on PIC16F84
Record and play fast 1-bit sound on a PIC micro
AT89C2051/4051scanning 7-segment display and keypad
AT89C2051/4051 Driving dot LED
AT89C2051/4051stepper motor interface
AT89C2051/4051connecting dumb terminal
Motorola 68K SBC (single board computer)
8051 SBC (single board computer)
Simple RS232C Level Converter using Transistors
Motorola 68HC11 evaluation board
C-52 EVB Robot Controller
Mains clock controller using AT89C2051
AT89C2051/4051 Easy-Downloader
AT89C51/52/55 Easy-Downloader
PIC16F84 programmer
PIC16F84 miniature real-time controller
Isolated RS232 for PIC16F84
PIC16F84 debugging terminal
Analog datalogger based on T89C51RD2
Atmel 89C Series Flash Microcontroller Programmer
Atmel 89C2051 prototype board
AT89C2051 real-time controller
PIC12C508 Night-light saver
AT89C2051 Night light saver
Atmel 8051 Flash Based-Microcontroller Programmer
AT89C2051 Digital thermometer and clock
4-Channel Timer using Atmel 89C4051 and MAX7219 display driver
PIC16F84 CW decoder (PDF)
12C508 Smart Lock
80C31 stepper motor controller
Build a PIC controlled DDS VFO, 0 to 6 MHz
PIC controlled DDS VFO, 0 to 6 MHz
Basic Stamp Lightning Activity Monitor
Parallel AVR programmer
PIC16F84 line following robot
PIC16C505 IR / wireless remote control
Automatic door opener with PIC12C508
RS485-like multi-drop bus with half duplex serial protocol
WWWpic2 - A web server in a PIC
PIC16F84 web server
50 MHz frequency counter, voltage meter & SWR/PWR indicator
Microcontroller board using the Atmel AVR AT90S8535
Programmer PIC16F84,12C50x and EEPROM 24Cxx
RDS Encoder - digital part
PIC programmer for serial port
Fully functional PS/2 mouse based on the PIC16F84
PIC 18 programmer (PIC18F458, PIC18F452, PIC18C252, PIC16C745, PIC18F6620, PIC18F6720)
Foreign vocabulary recollector
Illuminate holiday destinations on a world map
Embedded system to send e-mails (small TCP/IP stack)
Speaking clock using PIC & ISD device
Speaking doorbell using PIC & ISD device
Whistle detector using 8-pin PIC
PIC16F877 to IDE interface
68HC11 stepper motor control
90S2313 AVR Robot Board
POCSAG encoder/decoder
Network Time Protocol AVR Clock
DS1820 Temperature Sensor Readout Unit
Rotating Sprocket Wheel Generator (PIC16F84)
Talking PIC - based on SP0256
Serial to parallel converter using the AT89C2051
AT89C2051 serial COMs to LED driver
PIC16F877 Programmer And Development System
DS1820 Arbiter V2.00 Schematic
Microchip PIC ICSP implementation
101 AT Keyboard to ASCII Decoder using 68HC705J1A MCU
LCD Serial Terminal
Propellor clock (PIC16F84)
Optical sensor using PIC12C508
Interfacing S-7800A to PIC16F877
A Scenix (and PIC) Programmer
MMC to PIC16F876 circuit diagram
8088 maximum mode SBC
EZ80 single board computer schematic (Z80)
8051 Development System Circuit Board
Voice recording and message retrieval system
Interfacing a GPS to an LCD using a Microcontroller
Long-period watchdog timer
PIC16F84 Range Finder Project
Generate video signals in real-time using a PIC16F84
PIC Project #1 - RS232 to I2C Interface
Galvanic decoupling of I2C bus
Programmer PIC16F84,12C50x and EEPROM 24Cxx
Dual PIC16C84 prototype board
Graphic LCD interface
FSK modem with PIC16C84
Talking YODA project (PIC16C84)
Microcontroller interface for 5KW microwave oven
Using an I2C Serial EEPROM with a Basic Stamp 2
PIC16F84 Based Morse Code Reader
AVR-Based Serial Port IR Receiver
Interfacing piezo elements to a microcontroller
Victoria TAFE programmer (based on AT89C2051)
JDM programmer
PIC micro programmer
Speech recognition using HM2007
PIC microcontroller servo motor interface
PIC micro multiple servo motor interface
PIC16F84 countdown timer
PIC16F873 ultrasonic range meter
PIC16F873 Digital clock
PIC16F873 remote display
PIC16F84 stepper motor controller
Way small web server
PICADC - a free, PIC based "intelligent" A/D converter
8051 development system circuit board
8088 maximum mode single board computer (SBC)
Basic 89C2051 / 89C4051 circuit diagram
Debugging dump terminal for 89C2051 designs
Easy debugging terminal
Galvanic decoupling of I2C bus
Circuits interfacing piezo elements to a microcontroller
Driving a TRIAC using a PIC12C508
Isolated RS232C for PIC16F84
Microchip ICD (in-circuit debugger) circuit diagram
Microchip PIC ICSP implementation circuit diagram
Interfacing NMEA GPS to LCD using PIC16F84
PIC ICD (in-circuit debugger)
PIC16C71 morse code callsign generator
PIC16F84 to LCD interface
PIC16F84 I/O expander with PicBasic
Scanning 7-Segment & Keypad
10-key serial keypad encoder
Simple RS232C Level Converter using Transistors
Talking PIC microcontroller using SP0256
PIC-Programmer 2
Connecting PIC12C508 8 to 93AA46 serial eprom
KD7LMO Micro Beacon (PIC18F252)
GPS LCD Display Project
PIC16F84 LED chaser
PIC micro LED projects
PS/2 keyboard keystroke logger based on Atmel 89C2051
Electronic distance meter based on Motorola 68HC908QY4
Fan timer based on Motorola 68HC908QT2
Atmel AVR and 8051 series ISP programmer
AT89C2051 line-follower robot
Night light saver (PIC12C508)
USB and GLCD expansion board for 8051 SBC
Basic stamp interface circuits
Microcontroller sensor and actuator interfaces
Giant money counter (PIC16F876)
PIC12C509 logic gate replacement for nitrogen filler
PIC demo board
PIC12C509 Gym Timer
PIC LCD and Keypad driver
PIC12C508 Phase Controller for 2kW heater
PIC16F84 TRIAC / IGBT brightness phase controller
PIC16F84 pulse monitor with date/time output (ZIP)
Programmer for the 68HC705C8 MicroController
27c801 EPROM Programmer Project
LCD to PIC16C54 schematic
68HC11 based RDS decoder
Acceleration monitor using ADXL202 and AVR
40+ MHz 5-digit frequency counter with an AVR 2313
Interfacing DRAM to AT90S8515
Temperature monitor/controller: AVR 2313 / DS1621
PIC micro to ISA bus interface
PIC16C84 VT-52 Emulator for Linux
Microchip PIC ICD (in-circuit debugger)
Tony Nixons Pocket Programmer (PIC)
PicoWeb V5.1 (AT90S8515) tiny web server
Atmel 89C2051 In-Circuit Programmer Schematic
8051 Development System Circuit Board
8051 Development System Circuit Board
Microprocessor using Xilinx FPGA
Temperature controlled based on AT89CX051
I2C LCD interface
AFSK 1200 Modem based on PIC16C620
PicCon - Hidden Radio Transmitter Controller
PIC16F84 tone generator with source code
PIC16F84 tone generator
PIC16F84 tone generator (6-Bit)
AVR Beacon Super Keyer
AVR Frequency Counter
AVR Digital Voltmeter
AVR Signal Generator
Ser-Key 10-Key Serial Keypad Encoder
2-wire LCD interface using PIC16CF84
PIC16F84 Serial I/O-expander with PicBasic
RS 485-RPT Schematic
Camera remote control system using Basic Stamp
Low cost Atmel in-system programmer
Ultra low-cost programmer for AT90S family
AVR to USB interface
Programable LCD counter with memory backup based on Atmel AT90S1200A
Connecting AT90S2313 with LCD display 2x16 char and 4x4 keypad
Atmel AVR RCEN fuse bit programmer
Electronic safety lock based on ATtiny26
GSM SMS remote control using AVR microcontroller
128x64 LCD Driver for AT90S2313 (ZIP file)
Connecting LED to PIC Micro I/O pins (PDF)
Microprocessor RS-232 Reset
AT90S8515 experimenter board
Multi-chip programmer for PIC microcontrollers
Buffered PIC chip interface
A PIC-Based Keyboard Emulator
PIC-based robot
ScanMate audio activated recorded
PIC vacuum fluorescent display interface
PIC18F252 bootloader schematics
PIC16F876 Datalogger
GPS Repeater
Kodak DC-20 camera interface (PIC12C509)
Kodak DC-20 camera interface (PIC16F84)
PIC ICD in-circuit debugger circuit diagram
PIC programmers for parallel port
Wisp628 ISP Microchip PIC Programmer
WLoader - PIC16F877 application loader / bootloader
Nixie clock (PIC16F876)
Zilog Z80 thermostat embedded web server
Picxie 2 - 8x8 Animated LED Signboard (PIC16F84) Picxie 2 - 8x8 Animated LED Signboard
10 tricks for interfacing to the PIC16C508
Interfacing the PIC16C508
PIC 5x7 display
Analog to digital conversion notes
Multi-chip programmer

Various audio schematics (also see Music, Amplifiers, Preamp)
Electronic siren
Two-tone siren
Underwater microphone
Code practice oscillator
Noise generator
Electronic whistle
Twin-T Audio Sine Wave Oscillator
1.5V Audio Amplifier
Low Power Op-Amp - Audio Amp (Intercom)
555 Tone Generator (8 Ohm Speaker)
3 Transistor Audio Amp (50 milliwatt)
Low Frequency Sinewave Generator
Automatic Charger for Battery Operated Hi-Fi Preamps
Audio level indicator
Room noise detector
Amplifier timer
Bell ring generator
Amplified ear
Precision audio millivoltmeter
Six-channel Mixer and Amplifier
Audio Signal Source
Analog VU meter
Voltage controlled amplifier
Audio graphic equaliser
Intercom preamp
FET audio mixer
Microphone mixer
Tone control
Digital volume control
Sound level meter
CMOS IC audio oscillator
Three band Active Tone Control
Automatic gain control (AGC) circuits
Audio frequency meter
Bull Horn
Sound Mixer/Amplifier
Very loud beeper (PDF)
Digital noise generator (PDF)
Tone display system
Tube amplifier
Condenser microphone hookup
Phase shifter
Paradoxical Sound Syntheizer
Various tube crossover circuits
Bias circuits
Audio line isolator
Dynamic microphone to electret microphone input
Line level signal to microphone input adapter
Simple two line output combiner
Electret microphone powering circuits
Use amplifier phono input as line level input
Speaker signals to line level inputs
Spring reverb unit
Sine wave generator
Simple amplifier
3-Band equalizer
6-Input mixer
Doorphone intercom
Stereo line driver
Audio notch filer
Peak reading audio level meter
Tone control
Speaker Microphone Circuit
Electronic canary
Electronic siren
Microphone phantom power supply
Voltage Controlled Mixer w/Modulator
Dual Voltage Controlled Oscillator w/Modulator
Dual Voltage Controlled Filter w/Modulator
Stereo Ducker
MS Stereo Decoder
MS Stereo Microphone
RIAA Equalized Stereo Phono Preamp
Tube active crossover
Improved PL tone decoder
Magnetic cartridge amplifier
LM358 preamp
Sound detector
Tone detector
Tone generator
Voltage Controlled Panner
Low Noise Microphone Preamplifier
Bridging Adapter For Power Amplifiers
Simple Surround Sound Decoder
Simplest Ever Amplifier Bridging
Stereo Width Controllers
Power Amplifier Clipping Indicator
Phono Preamps For All
Digital Delay Unit For Surround Sound
Parametric And Sub-Woofer Equaliser
High Quality Sound Mixer
Loudspeaker Protection and Muting
Direct Injection Box for Recording & PA Systems
Minimalist Discrete Hi-Fi Preamp
Signal Detecting Auto Power-On Unit
Load Sensing Automatic Switch
Amplifier thermal protection
Active Sub-Woofer and Controller
Balanced Line Driver & Receiver
VU And PPM Audio Metering
Variable Amplifier Impedance
Linkwitz Cosine Burst Generator
Low Noise Balanced Microphone Preamp
Fast Audio Peak Limiter
Subwoofer Equaliser
Surround Sound Decoder Mk2
Audio mixer

Miscellaneous schematics
Ultrasonic radar
Mobile APRS / GPS tracking system
Electronic fish lure
Ultrasonic sound receiver
Experimental data transmitter for fiber optics
Experimental fiber optic receiver
Ion detector
Darkness monitor
Simple event counter
Geiger counter
Light detector
Short-circuit beeper
LM 1800 FM stereo decoder
Glitch detector
MAX924 bar-graph level gauge
Ultrasonic generator
Negative ion generator
ELF Monitor
Chaos generator
Simple BFO metal detector
Voltage Comparator Information And Circuits
Build Your Own Digital Setting Circles For Your Astronomical Telescope
PL tone generator (NE567)
Bat detector
Bat detector microphone pre-amplifiers
Full-duplex doorphone with 3 wires connection
G Strain energy absorber
RDS Encoder
Toggle Switch Debounced Pushbutton
Discrete Set/Reset Flip Flop
Monostable Flip Flops (one shot)
Discrete Bistable Flip Flop
Talking Morse Code Practice Computer
Plant watering watcher
Capacitance sensor
Whistle responder
Nocturnal animals whisker
12V DC electronic door chime
Biasing Op-Amps into Class A
Parasite zapper
Bleeper box for time reference
Analog computer
BayComm packet modem
Morse monitor
HamComm modem interface
Morse paddle keyer
UV light box
Hardware Random Bit Generator
Random noise generator
Analog pulse counter
Analog opto-isolator
Pulse width modulators (PWM)
Pulse width to voltage converter
Fantastic Atom Expander
Black Light
Computerize Your Room/Home
Flash slave trigger
Suddent ionospheric disturbance (SID) receiver
A Visual CW Zero Beating Aid
A two-way Morse practice set
Magnetic levitation device
Tesla power receiver
Lazer Tag Equipment Modifications
Garmin GPS data interconnect
Inexpensive APRS Weather Station
Walking robot
Basic op-amp circuits
Power line FM intercom
Intercom circuit
Lightning Storm Detector
Large LCD Display Buffering Driver
Text to speech converter
Ion detector
1uS light pulse descriminator plus F to V converter (PDF)
Broadband 2MHz optical fiber receiver (PDF)
Modulated light received (PDF)
1uS light pulse receiver plus post amp (MISC)
Broadband 5MHz optical fiber receiver (PDF)
High-speed light receiver (PDF)
Basement doorbell beeper (PDF)
Time to dust indicator (PDF)
Low-power optical interrupter (PDF)
Simple nitrogen spark generator (PDF)
Ultrasonic transducer oscillator circuit
Build logic gates using discrete parts
Jacob's Ladder
Sudden Ionospheric Disturbance (SID) Receiver
A selection of robotics projects
Bat detector (new)
Vat detector (old)
Variety of quick designs
Gold wafer (smartcard) programmer
Making a FRED photopopper
GPS receiver support kit
Griffith Observatory Tesla Coil
Fogger smoke machine
Dinsmore 1490 digital compass
Geiger counter
Electric field disturbance monitor
Inexpensive seismometer project
Digital dial
Speech recognition using HM2007
GPS receiver interface
Doorbell for the Deaf
Electromagnetic field detector
Insect Repellant
High Quality Intercom
Magnetic Gun.
Metal detector
Static Electricity / Negative Ion Detector
Ultrasonic dog whistle
Popular Electronics Ultrasound Detector
An Inexpensive X-ray Machine
Navigator 555A radio direction finder (RDF) circuit diagram
Magnetic levitation circuit
PE3342 Programmer Schematic
u-Blox GPS receiver board
Assorted digital circuits
Basic electronic circuits
Miscellaneous simple circuits
Digital Call Sign Annunciator
Monitor output from Motorola Oncore GPS engine in HP Z3801A in GPS Disciplined Oscillator
Ultrasonic switch
Sound finding cricket with phase detector
Sound finding cricket
APRS GPS tracker schematic (PIC16C73)
Common Ground for Older VPW Circuit
Very basic circuits
Bat detector
FCTS Project
Smooth Tone Clickless CW Sidetone Generator
Morse Code Beacon Keyer
Lightning Activated Camera Shutter Trigger
Simple metal detector electronic circuit
Three Power Supplies for the Garmin GPS-20 Sensor Board
Driving N-channel FETs from TTL
Miniature Self-Powered Autonomous Robot
Morse Code Practice Keyer 1
Morse Code Practice Keyer 2
741 Light Sensor
Fluid level detector
The Aisin-Seiki GPS-Receiver (The "US$20 GPS")
Morse code display
Intercom schematic
Scaling ADXL50 accelerometer output

Model and remote control schematics
Snake throat muscle controller
Handy cricket for robotic applications
Incline Railway Control Circuit
A Receive Signal Decoder
27Mhz toy car receiver
27Mhz toy car transmitter
One ounce rocket ejection timer
LED traffic lights
Two-tone siren
Proportional radio remote control
Alf: The Robotic Matchbox car
Seaplane schematic
Model Rocket with Video Camera
Signal breaking module
RF serial link for robot
PIC based rocket altimeter
Robot with PIC16F84 brain & InfraRed eyes
0-10V control for RC servos
Robotic microcontroller board
Multi Rocket Launcher
Model rocket launch controller
Pad launch controller for model rockets
Simple flashing light circuit
Simple flashing light circuit
A dual alternating flashing light circuit
Simple flashing light circuit
A dual tandem flashing light circuit powered by a 9 volt battery
Simulate the Gyralite (dual flashing headlights).
Simple train detector using ambient light and a photocell
Simple charge rate monitor
Deluxe charge rate monitor
"CLONEPAC" memory module for Futaba 8UAF/8UAP
Battery pack discharger
Plane locator
Plane locator 2
Battery low voltage alarm
Battery low voltage alarm 2
Ultimate battery low voltage alarm
R/C digital camera controller
R/C helicopter camera
Building an RF Remote Control System
Motor walker circuit
250-amp Speed Controller for RC cars
Spider robot electronic project page
Two tone train horn
R/C Emergency locator alarm
Remote switch for radio-control aircraft accessories
Radio Control Battery Backup
Glow Plug driver for model engines

Motor and general control schematics
Bridge head
PWM motor controller
Transistor relay driver
Latching relay driver
Relay delay circuit
Touch switch
Low voltage DC motor speed controller
Flashing neon christmas lights
Three input first response monitor
Switch-on delay circuit
Electronic thermostat
LM3911 temperature controller
Programmable light-activated relay
Simple 10 Stage Control Box
One component stepper motor driver
Dual Stepping motor drivers using UDN2540
PWM DC motor control with SG3525
Stepper Motor Driver using TEA3718/3717
Microstepping with PBM3960 and TEA3718
DC Motor Driver with L6203
Stepper Motor Driver using L298 and L297
Several stepper motorol control circuits
Wireless RF PWM dual motor controller
H Bridge Motor Control Circuits
Motor speed controllers
Ceiling fan speed control
Delayed off light switch
Deoderizer fan timer
Electronic Thermostat Relay Circuit
Interfacing 5 volt CMOS to 12 volt loads
Light Activated Relay
CMOS Toggle Flip Flop With Relay(CD4013)
555 Timer Monostable Circuit Using Pushbutton
Dual Channel Servo Pulse to H-Bridge Interface
Current loop interface
Switching solenoid driver
Modular relay system
Light/dark detector
Pulse Width Modulation DC Motor Control
Stepper motor controller
Touch switch
Pump controller
H-Bridge motor controller (5 amps, 100 watts)
Dual Channel Servo Pulse to H-Bridge Interface
Servo pulse to PWM converter
12V Sump Pump Control
Rolling code 4-channel UHF remote control
DC Motor Speed Controller
3 Phase Brushless DC Motor Xtal Based Controller
DC motor controller
Garden moisture controller
Overload Voltage Protection with Automatic Reset
Pulse Width Modulator
Pulse Width Modulator Motor Speed Control
Pushbutton one-shot and latch (PDF)
Charge coupled bi-directional power MOSFET relay (PDF)
Finger touch activated switch (PDF)
Machine vibration triggers hour meter (PDF)
Solid state relay (PDF)
Line-powered Xenon flash transmitter (PDF)
9V Xenon photoflash controller (PDF)
AC switching with TRIAC from TTL
Control 120VAC relay with TTL
Driving a relay with a CPU
Power-line Appliance Controller
Simple Switched Servo Driver
Combination-controlled, fully customizable RF remote control
Thermoelectic controller (scriptable thermometer)
Stepper motor positioner
Stepper motor driver
Frequency switch
PIC16F84 RF remote controller
Stepper motor controller
H-Bridge shematic
DS1821 programmable thermostat
Hot Water Tank Indicator
Temperature monitor
Cold activated switch
Voltage comparator switch
Dark activated switch
DC Push Button Motor Control Circuit
Light detector
DC Motor Reversing Circuit
Sound operated switch
LDR light/dark activated relay switch
Touch Switches
6090 digital decoder schematics
Assorted relay control circuits
Adjustable Voltage motor controller
Serial servo controller
DC Motor-Driver H-Bridge Circuit
PWM Motor Speed Controller / DC Light Dimmer
Constant Temperature Circuit
PWM DC Motor Speed Control
Solenoid starter
CO2 controller for planted tanks
Light activated relay
Delayed shutter control for Kodak DC-20
Gasoline generator automatic throttle controller
Block power switching module
MOSFET H-BRIDGE schematic and theory

Music related schematics (also see Audio)
Audible metronome
Visual metronome
Peak-reading meters
Octave screamer
Amiga MIDI interface
Apple Mac to MIDI synthesizer interface cable
Apple Macintosh MIDI interface schematic (basic version)
Apple Macintosh MIDI interface schematic (deluxe version)
Standard MIDI to MIDI interface cable diagram
Simple MIDI switcher
MIDI interface / cable tester
MIDI keyboard
MIDI merger schematic
25-pin PC serial port to MIDI synthesizer interface cable
9-pin PC serial port to MIDI synthesizer interface cable
Serial MIDI interface
Microcontroller MIDI interface
MIDI keyboard circuit
Spring reverb unit
Colour organ light
MP3 Player
Metronome and pitch generator
Mini metronome
Compact Flash / IDE MP3 Player MKI
Simple colour organ
Guitar fuzz effect
8 note tune player
Colour (Sound) Organ
Transisor organ
BookPC Car MP3 Player
Yet Another Mobile MP3 Player
Wave Multiplier for music synthesizers
Vibrato Circuit for Guitar, Steel, Bass, Etc.
MIDI status indicator
Zonk Machine and Treble Booster
Simple line mixer
Simple MIDI tester
MIDI Controller Footpedal
DIY Serial MIDI Interface (80C51/80C31 Version)
Electronic metronome
Sound Effects Generator
Sound Effects Generator 2
Digital Guitar Tuner
Drum tone oscillators
Analog MIDI synthesizer
Spring reverb
MIDI to CV interface
Dual phantom power pre-amp
Four channel fuzz box
Theremin controller
Vocal zapper
MIDI drum machine project
MIDI Drum Machine Analog Input Schematic
Guitar Reverb Pedal
Guitar Tremolo Unit
Spring Reverb Unit For Guitar
Ultra Simple Bass Guitar Compressor
Vox AC30 Guitar Amplifier Simulator
Guitar Vibrato Unit
Musical Instrument (Expandable) Graphic Equaliser
Midibox 64

PC related schematics
I2C printer port adaptor
RS232C Level Converter
PC electrically isolated RS422 interface using SN75176B or MAX485
PC electrically isolated RS485 interface using MAX487 or SN75176B
Short circuit protected power supply from PC 12V supply
Isolated Full Duplex RS232C Interface
RS232 DB-9 switch to flip between two serial ports
DB-9 Connector to DB-25 (both RS-232)
Mac Serial Port (RS-422 DIN-8) to RS-232 DB-25
Modem Rockwell RCV336/ACF model V1433VQR ext.
Genius Mouse schematics
EEPROM programmer
Commodore 64 24-bit parallel port interface with 8255
Sound Card Interface with Tone Keyer
RGB oo Monochrome converter - Matches impedance of PC to CCTV monitor
Ericsson phone to PC serial port interface
PC serial port receiver
Parallel port relay interface
ISA 48 I/O digital card
PC infrared iRDA interface using TFDS 4500
Jupiter card programmer
USB to RS232 Dongle
Parallel (Printer) Port Interface
RS-232 line monitor and loopback cables
The KD2BD Pacsat Modem
A Serial Infrared Remote Controller
PC Serial and Parallel Port Software and Interfaces
Interfacing 16x2 character :LCD to parallel port
RS-232 Protocol Analyser
Interface cable for Casio QV-200 digital camera
Radio clock for PC's
A PC-Based LowFER Frequency Synthesizer
General purpose 48-bit ISA parallel I/O card
Power from RS-232 port
PCI to ISA converter
WatchDog for ISA Bus
4-channel 8-bit analog-to-digital converter for PC
Printer port ADC
Parallel port ADC based on MAX147
Analog Signal Acquisition for PC Printer Port
More accurate PC/AT clock
Getting power from RS-232 interface
Barcode scanner
Build your own iRDA SIR Transceiver (Dongle) using MCP2120
PC thermometer
Dive computer interface
Parallel port servo controller
GPS receiver (Gamin, Eagle etc) to PC interface cables
Connect two CD-ROM drives to one soundcard
Headphone driving circuit for soundcards
Get power out of PC parallel port
Null Printer Adapter
PC speaker volume control circuit
How to get power from PC to your circuits
RS-232 surge protection
Simple RS-232 serial port buffer circuit
Get power out of PC RS-232 port
Sound Blaster Microphone Preamplifier
Sega 3D glass interfacing circuits
Convert Atari-style joystick to PC joystick port
Fake Joystick circuit
Using the joystick port as general purpose input
Connect other circuits to PC joystick port
Schematic of a standard PC joystick
Simple PC SmartCard reader
Fax to modem interface
Analog to Digital Conversion (ADC) and Communicating with a PC
Temperature sensor for PC
Interfacing to an IBM PC/AT keyboard
PC interface for point controller
Linux Infra-red Remote Control (LIRC)
Homebuilt RS232 LCD Interface
Compter microphone
CCD linear image sensor to PC parallel interface
Laptop Computer Serial Port Power Booster
Assorted computer interface circuits
HamComm Interface
Apple II/II+/IIe IDE Drive Interface
Basic Stamp I & PC Relay Controller
RS-232 to TTL cable
Hi-Fi PC Speaker System
IDE hard-disk interface for Amiga 500
How to construct Garmin GPS receiver interface cables
iRDA printer adapter
160 Baud ALDL Hardware Interface
AT PC Power Supply 1
AT PC Power Supply 2
AT PC Power Supply 3
AT PC Power Supply 4
AT PC Power Supply 5
iLINK Interface
Digital Signals Decoding Interfaces
9-pin null modem cable
RS232 - Lowe HF-225 interface
RS232 to IrDA convertor using Vishay TOIM3232
Interfacing PC sound card to SSB rig
Supply Derives Power From 3-Wire RS-232 Port
24-line PC digital interface (PDF)

PDA interfaces and related schematics
Casio interface circuits
SHARP palm-top/hand-held to RS232 serial converter
Interfacing ultrasonic range finder to BrainStem
Hamamatsu UVTron Interface to a BrainStem
Casio interface cable
Casio organiser hardware
MIDI interface for Palm computers
MIDI interface for Palm cradle
MIDI interface for Visor USB
MIDI-USB Cradle for Visor (Deluxe, Platinum)
MIDI interface for Visor
Casio datalogger
Interfacing ADXL202 accelerometer to PalmPilot
PalmPilot audio interface
PalmPilot cradle to modem adapter
PalmPilot connector pinouts
PalmPilot serial port interface
PalmPilot memory schematics
Aladin interface
PalmPilot turbo boost guage interface
IBM PC keyboard to PalmPilot interface
Aladin interface using op-amp
Wireless local network for PalmPilot (large PDF)

Power supplies and control schematics
Power supply provides +5VDC regulated, +10VDC unregulated and 7.5VAC
13.5KV power supply
Kirlian device supply
LM317 adjustable power supply
LTC1265 Nicad charger
Single cell lithium battery charger
Smart battery charger
Battery charge indicator
Lead acid trickle charger
12B Battery condition indicator
Alkaline battery charger
Alternative power source for Magellan GPS receivers
Power Tool Torque Control
Generating Negative 5 Volts from 9 Volt Battery
LED Battery Condition Indicator
LM317 Variable Voltage Regulator
LM317 Regulator With Pass Transistor
High Current Regulated Power Supply
Simple Variable Voltage Source
Various switching power supplies
Variable 3 - 24 Volt / 3 Amp Power Supply
2 watt switching power supply
Variable Voltage and Current Power Supply
Low Power DC to DC Converter
Constant Current Battery Charger
Intelligent NiMH/NiCd switched mode fast charger
Variable DC power supply
Nicad battery charger
Simple power supply
Voltage converter
Bench power supply
Easy power supply
Valve power supply
6V to 12V Converter
Tesla coil / HV generator
High Current Power Supply
Dual Polarity Power Supply
High Voltage High Current Power Supply
Transformerless Power Supply
Fixed Voltage Power Supply
Voltage Inverter
Voltage Inverter
Dual power supply
1A Variable Regulated Power Supply
Negative voltage generator
12V battery capacity tester
NE555 Low Voltage Battery Disconnect Circuit
33 Volt DC To DC Converter
Automatic AC voltage (110/240) selector
Variable 0-5A Current Source
Ground Fault Interupter
Intelligent battery charger
12 Volt DC Load Control and Battery Protection
Low battery indicator
Variable power supply
Switching Power Supply
Low Power DC Quadrupler
Surge protector
Ultimate power supply
Variable Regulated Power Supply
Power reminder beeper (PDF)
Unplugged power cord alarm
Machine power loss beepter (PDF)
Low-dropout 12V regulator (LM324)
HV supply: 12VDC in, 12KV out
Generating -5VDC from +5VDC
Filtering PC bus POWER
Bidirectionall power inverter
Nagative voltage generation using 555 timer
High current regulated power supply
One 9V battery gives +18, +25, +33V
+9V *and* -9V from one battery
Battery charger
Adjustable power supply using LM317
Simple +5V power supply circuit
12 Vdc - 120 Vac Inverter Schematic
+12V/-12V Power supply unit
+/-12V -> +/-5V Power unit
+5V Switching regulator (1)
Switching regulator (2)
Electric power controller
+30V power supply with +5V
+30V DC-DC converter
DC/AC inverter (2)
DC/AC inverter (1)
PIC16F873 DC motor speed controller
12V 30A power supply
Dual regulated power supply
Fuse blown indicator
Gyrator circuit
Variable power supply
LM317 Regulator Circuit
Nicad battery charger
Regulated 12V supply
Unregulated power supply
Snowmobile GPS power adapter
Simple switching power supply
Assorted power source and control circuits
12 volt battery monitor
12 volt power supply
5 volt power supply
Battery voltage monitor
LM3914 battery monitor
Multiple voltage power supply
Voltage doubler
Voltage inverter
PWM Motor Speed Controller / DC Light Dimmer
PWM Motor/Light Controller
Low Power LED Voltmeter
PWM Motor/Light Controller
PWM Motor/Light Controller variants
Low Power LED Voltmeter
Temperature Controlled NICD Charger
Simple Capacitance Multiplier Power Supply For Class-A Amplifiers
Simple DC Adapter Power Supply
Variable Dual Lab Power Supply
Battery Charger Ideas
Power control for arc welders and other inductive loads
Charger for gel lead acid batteries
Nicad battery cycler
Battery Characterizer
Nicad Battery Discharger/Capacity Indicator
200 Watt Modified PC Power Supply 13.5 Volt 14 Amp

Radio-frequency schematics (also see Transmitters)
UHF oscillator
Economoy short-wave radio
Linearized RF detector
Two-band radio
Shortwave conveter for scanners
FM Bug
AM Radio
Toroidal coil RF shortwave receiver
Crystal radio
CW RECEIVER 40/80 meter CW receiver
TRF AM Receiver circuit
WLW 500KW Transmitter Schematic
AM-Receiver for Aircraft communication (118.250MHz)
AM receiver for aircraft communications
45-860MHz Radio receiver based on UV916-tuner
80 Meter CW ARDF receiver
Four channel RF remote control
CW zero beat indicator (PDF)
Build your own VLF Receiver
Receiver building blocks
Simple wireless radio data link
RX3302 receiver module schematic
Superregenerative 27MHz receiver
49MHz walkie-talkie
Convert 2m VHF FM PMR transceiver Motorola Radius M110 into an amateur radio
Vibrating pocket bug detector
2MHz RF Oscillator
50-150MHz Overtone Oscillator
Simple Op-Amp Radio
UHF - 100W Transistorized amplifier
50MHz Converter
RF front-end for triple conversion GPS receiver
2M - 20M transverter
Improved CMOS RF PLL sythesizer
Harmonic oscillator
Direction finder system
One transistor regenerative receiver
Synthesized HF receiver
TBA120 narrowband FM receiver
TDA7000 receiver
ZN414 receivers
10W HF linear amplifier
500W HF linear amplifier
3W HF QRP linear amplifier
Phasing SSB exciter
500mW HF linear amplifier
Generic VHF power amplifier
10.7MHz FM detector
RTTY terminal unit
CMOS RF PLL sythesizer
3W FM Transmitter
Crystal radio
Op-Amp Radio
Car radio tunes the Amateur Bands
Crystal set that requires no antenna
80m Direct Conversion Receiver
A compact L-match ATU for portable use
Morse Adaptor for your VHF/UHF FM rig
An end-fed antenna, L-match coupler and resistive bridge for HF
AM Broadcast Band Regenerative Receiver
50 MHz to 146 MHz Converter
Hear Amateurs on your Shortwave Radio!
Compact 20 14 MHz direct conversion receiver
Hear Amateurs on your FM Radio!
RF actuated CW monitor
LF to HF Converter
Super 80 ultra-simple SSB receiver for 3.5 MHz
Class B series modulator
L-Band PHEMT LNA for GPS, Inmarsat etc
Advanced VHF power meter
The MRX-40 Mini Receiver
23cm Data Transceiver
External antenna for the GPS-38, Magellan 2000, or Eagle Explorer GPS receivers
AM Broadcast Band Active Antenna
Active antenna with gain
Ham Band VFO
HF Signal generator
Simple AM Radio Receiver & Amplifier
Bug detector
175KHz inductive pulse receiver (PDF)
200-400 MHz voltage controlled oscillator
AM/FM/SW active antenna
RF Sniffer <.5 to >500 MHz
Demodulator Schematic/Design
AM BCB radio receiver
Regenerative shortwave receiver
7MHz SSB Transceiver
DSBSC (Double Side Band Supressed Carrier)
Frequency Synthesizer
Digital Automatic Gain Control (AGC)
Four Channel Wireless Transmitter and Receiver
Talking receiver
PLL synthesizing oscillator (1)
PLL synthesizing oscillator (2)
PLL synthesizing oscillator (3)
2N2222 40 Meter CW/DSB Transceiver
Yaesu FT-736R doppler compensation
Phased lock loop schematic
30M PSK31 Transceiver
SOP receiver (PDF)
SOP direct conversion receiver
30m direct conversion receiver
Popcorn direct conversion receiver
40m direct conversion receiver
80m direct conversion receiver
Huge LED Antenna Direction Display (part 1)
Huge LED Antenna Direction Display (part 2)
136 kHz direct conversion receiver
One Watt 2.45 GHz Linear Amplifier
222 MHz Transverter
VFO from 2001 ARRL Handbook, page 17.74
VFO from 2001 ARRL Handbook, page 14.20
Assorted RF circuits
14MHz SSB 10mW Transceiver
Building a Simple LF Exciter
Yaesu band decoder schematic
23cm Wide-Band FM data transceiver for high-speed packet-radio
VLF radio receiver schematic
5 watt, 80 meter QRP CW Transceiver
How to Build a 300MHz AM, RF Remote Control System
RF Modem Robotics Project
PLL FM transmitter
ICOM CI-V interface with RS232 RTS to PTT
Improved FM Stereo Modulator
Smooth Tone Clickless CW Sidetone Generator
Variety of receiver converter projects
One transistor FM receiver
42 Mc Band to 88 Mc Band (retrofit converter) Project
Crystal radio circuits including diode performance comparison
50MHz Assistant (Preamp & Power Amp.)
Bug detector
Basic RF oscillator
Radio Control Electric Switch
56K RF Modem
80M ARDF direction finder

Solar-powered schematics
Sun tracking circuit for solar arrays
Solar power recharger
Solar power supply
Solar charge controller
Solar robots
Solar Tracker
1381 solar engine
D1 solar engine
FLED solar engine
PM1 solar engine
Solar car array controller schematic
Solar car battery monitor schematic
Solar car brake controller schematic
Solar car main controller schematic
Solar car display controller schematic
Solar car electrical design and circuit index
Portable solar battery charger
Sensor Electronic Tracker with H-Bridge Drive
Sensor Electronic Tracker with Simple Solar Charge Controller
Solar tracking control system
LED7 solar tracker
Solar step-down regulator
Zener-based solar engine
AA battery solar charger
AA battery solar charger
Solar Panel Charge Controller / Low Voltage Disconnect Circuit
Solar Panel Current Meter
SCC2 10 Amp Solar Charge Controller
Solar Charged LED Flashlight
AA battery solar charger
Solar Panel Charge Controller / Low Voltage Disconnect Circuit
Solar Panel Current Meter
Solar cell Nicad charger
Solar powered dock lamp flasher

Telephone and intercom related schematics
Telephone recording circuit
Infinity Transmitter Schematic and Plans
Digisound ring modulator
Incoming call indicator
Telephone Ring Generator Using 60Hz Power Transformer
Telephone Ring Generator Using Switching Power Supply
Telephone In-Use LED Indicator
Telephone In-Use Relay Circuit
Telephone Audio Interface
Telephone interfacing / caller ID using a PIC microcontroller
Home made PBX / PABX
Ringing Phone Light Flasher
Phone Busy Indicator
FM Telephone Bug
Cut Phone Line Detector
Simple Phone Tap
Telephone Hold Button
Telephone Recorder
300 baud modem circuit schematic
DTMF Generator/Decoder
Interface cables for various cell phones
Telephone music on hold box
Telephone ring controlled relay
1-line telephone status indicator (PDF)
Line in use indicator (PDF)
4-line telephone status indicator (PDF)
Caller ID decoder
Telephone in use light
Detecting a telephone RING
Phone In-Use Light
Phone to audio interface
Phone Off-Hook Indicator
'phone rang' indicator light
Phone Line to Audio
Phone in-use
Telephone Line Monitor
Use old phones as an intercom
Phone-In-Use indicator
Hold function for Telephone
Digital/Standard Phone Line Tester
Caller ID decoder part 1
Caller ID decoder part 2
DTMF decoder / logger
FM telephone bug
Universal telephone hold
Talking phone dial monitor
Telephone line simulator
Telephone privacy adapter
Telephone ringing circuits
Simple circuit to connect telephone equipment to audio mixer
NCDS Interface Schematic for Nokia 3110, 8110, 8110i
Assorted telephone circuits
Greek telecard reader
Phone ring circuit schematic
Cut phone line detector
Telephone autodialler
Taxi phone automatic dialler

Test equipment schematics
Audible continuity tester
Wire tracer
Signal generator for signal tracer
Electronic level
Digital volt meter
Adjustable continuity tested
Frequency counter
Tri-Waveform Generator
220V live wire-in-wall scanner
Owens Bridge Inductance Measurement Device
ESR Meter
Line Output / Flyback transformer tester
PC-Based Digital Storage Oscilloscope (DSOA)
PC Based Digital Storage Oscilloscope Mk3
Simple 6-Digit 40MHz Frequency Counter Module
Automatic stud detector
Capacitance meter
Capacitance meter
AC Line Current Detector
Triangle and Squarewave Generator
Signal tracer / injector
Voltage probe
Live line detector
Grid dip meter
PCB VSWR bridge
Electric field & leakage detector
Simple polarity detector
RCM710 Electronic Scale
3 - 12 MHz Signal Generator
Some simple test equipment to build
RF Power Meter for the QRPer
Dip Oscillator for HF
Two Tone Audio Oscillator (use for SSB tests)
Simple pH meter
Temperature compensated pH meter
pH meter with calibration
Four Channel Oscilloscope Adapter
Arbitrary Waveform Generator
Digital Pressure Gauge
Remote Field Strength Meter
Digital frequency counter
Function generator
High / Low indicator
AC/DC LED Indicator
Micro ohm meter
Micro volt probe
MOSFET tester
Power factor meter
Ramp generator
LASER/LED light output intensity meter (PDF)
Frequency and capacitance meter
Resistor decade box
Simple light sensor adapter for oscilloscope
Time Domain Reflectometer (TDR)
40MHz frequency counter using Atemel AVR 2312 microcontroller
pH Meter
Multi Wire Cable Tester
Connection tester
EMF field probe
Function generator
Logic probe
Zener diode tester
Mini DDS (direct digital synthesizer)
LCD frequency counter (PIC16F84)
Pulse Reading Logic Probe
Pink Noise Generator for Audio Testing
Audio Millivoltmeter
Audio Test Oscillator
Full Featured Transistor Tester
Opamp Design and Test Board
Microphone Circuit Test Oscillator
Distortion Analyser
Self Oscillating Amplifier for Distortion Testing
120MHz frequency counter
Capacitance meter that connects to multimeter
Transistor tester and signal injector
Continuity tester
Square wave oscillator (555)
Build a Magnetic Field Immunity Tester
555 Timer IC Tester
555 go / no-go tester
12V Lead-Acid Battery Monitor
Continuity tester 2
Continuity tester
Logic probe
4-channel DSO for oscilloscope
Field strength meter for the 137 kHz band
In-circuit electrolytic tester
PIC logic probe with pulser

Timing, oscillators etc schematics
Budget timer
Long period timer
555 time delay circuit
Low frequency clock
Countdown timer with relay
DDS using AD9835
1 Second Time Base From Crystal Osc.
Power-On Time Delay Relay Circuit
Low Voltage , High Current Time Delay Circuit
Power-Off Time Delay Relay Circuit
Generating a Delayed Pulse With a dual 555 Timer
1KHz Sinewave generator
Timed beeper
GPS receiver clock circuit
Time Delay Relay
Time Delay Relay
Wide-swing Variable Crystal Oscillator
Circuit that momentarily closes a pair of contacts at long intervals
Onboard Fogger Timer
Colpitts 1 to 20 MHz Crystal Oscillator
Divide By 1-1/2 Circuit
Simple sinewave generator
Two Transistor Sine Wave Oscillator
10 Hz to 10 Khz VCO with Square and Triangle wave
Line powered 60Hz clock generator (PDF)
Micro-power pulse generator (PDF)
Darkroom camera shutter timer
Divide by 1.5 counter (PFD)
High-output square wave generator (PDF)
D Flip-flot one-shot circuits (PDF)
Clock divider
Clock doubler
CMOS oscillator
Crystal 32.768KHz CMOS Oscillator
Crystal oscillator
Cheap 40KHz clock
Stable 40KHz clock
'Rounding Off' a square wave
Switch debounce using 555
Square wave to sine wave converter
Day / Night / 24 Hour Select Sensor
One transistor timer
Variable timer
Micropower pulse generator (PDF)
Square wave oscillator
Triangle wave oscillator
Sawtooth wave oscillator
Sine/Cosine wave oscillator
555 timer
555 oscillator
Stable multivibrator (IC)
Stable multivibrator (Transistor)
Timer based on Microchip PIC16F628
Push Button Switch Debouncer
Square wave oscillator
5 to 30 Minute Timer
NE555 Basic Monostable
Mini DDS (Direct Digital Synthesis)
Astable Multivibrator
High Precision GPS/TV controlled Reference Oscillator
TV based Receiver for a Standard Frequency Generator
AD9852 DDS schematic
A GPS receiver based frequency standard
Monostable multivibrator
Clock generator
555 Timer Tutorial + Circuits
Versatile electronic timer

Transmitter schematics (also see RF)
Li'l 7 AM Transmitter Schematic
Wireless microphone
XTAL locked tone transmitter
AM oscillator for wireless microphones
Wireless microphone
1W CW Transmitter
433MHz transmitter using SAW resonator
A 3m (100 MHz) small bug
Basic FM Transmitter
Micro Power AM Broadcast Transmitter
FM Beacon Transmitter (88-108 MHz)
1 valve CW transmitter
250mW HF CW transmitter
2 valve CW transmitter
Transmitter using LM317
5 Watt HF CW transmitter
Simple FM microphone
FM bug
High power FM bug
27MHz AM/CW transmitter
Easy 2-meter transmitter
QRP HF transmitter
Spark gap transmitter
QRP SSB transmitter
Crystal controlled FM transmitter
150mW FM transmitter
FM transmitter
Two Valve 40m CW Transmitter
Frequency agile 80m CW QRP transmitter
80 metre DSB transmitter
One Valve CW transmitter
Simple Low FER Transmitter
7Mhz AM/CW Amateur Radio Transmitter
VHF FM transmitter
Simple FM transmitter
Wireless microphone
Shortwave radio transmitter
175KHz inductive pulse transmitter (PDF)
7MHz QRP transmitter
Small Radio Transmitter
FM Telephone Transmitter
Tracking transmitter
5W PLL Transmitter
Miniature FM transmitter
Sensitive FM transmitter
Simple RF transmitter
1.5 volt tracking transmitter
Tracking transmitter
Micro Power FM Broadcasting Circuits
Low Power FM Transmitter
RF/SS Handie Hopper Transmitter Schematic
30-Meter QRP Transmitter for Morse Code
Miniature FM Transmitter #1
Miniature FM Transmitter #2
Miniature FM Transmitter #3
Light sensing RF transmitter
Micro-Spy with FETs
Micro-Spy with USW
Micro-Spy with TTL

Back to top or discuss AM and FM Transmitter schematics in our Forum!

Video related schematics
Video Clock Superimposer
Video clock superimposer using PIC16C711
Simple AV (audio / video) wireless transmitter
Audio / video distribution amplifier
10GHz video link
Experimental macrovision remover
8 x 8 Audio-video switch
VHF/UHF TV modulator
LH0032 video amplifier
LM359N video amplifier
Macrovision code remover
Driver for multiple VGA monitors
CCD (charge coupled device) support board
Closed-Caption Decoder
PIC-Tock video clock
Video/Audio Wireless Transmitter
Video signal amplifier
RGB video digitizer
Color Bar Generator
Microcontroller test pattern generator
NTSC Video Distribution Amplifier
Commodore RF modulator
Video signal edge enhancement
Video amplifier
Video/Audio Wireless Transmitter
4 Stage 555 Timer for Video Cam Control
Digital volt meter with video output
TV/Radio antenna cable galvanic isolator
S-video to composite video adapter
VGA converter for video projectors and fixed frequency monitors
VGA to TV converter
VGA to PAL and NTSC converter
PIC micro frame grabber (TDA8708)
Low cost audio/video modulator and transmitter
Many video amplifier circuits includiing transmission over UTP (PDF)
Commodore 64 Video Modulator 251025 Schematics
Commodore 64 Video Modulator 251696 Schematics
TV RGB signal output from a SVGA graphics card
Macrovision removal
AVR (AT90S2313) composite PAL colour bar generator
Homebuilt video digitizer Mark I
Homebuilt video digitizer Mark II
TV transmitter (PDF)



Pirate Radio kits FM Transmitter schematic hobby broadcast RF Circuit Antenna Surveillance spy
Links for FM Transmitter Kits, Circuits, Electronics ...


Kit Manufacturers and Resellers :
Broadcast Warehouse : FM PLL Transmitter Kits, Stereo Coders, Prebuilt systems
Veronica Kits : FM PLL / VCO Transmitter Kits, Stereo Coders, Prebuilt systems
NRG Kitz : FM PLL / VCO Transmitter Kits, Stereo Coders, Prebuilt systems
L.D. Brewer : Resells kits made by most major UK / US manufacturers
Free Radio Berkeley : Make a PLL kit and some Amplifier kits. Circuit Dias on the Net.
Panaxis : American manufacturer of FM Exciters
North Country Radio : FM and AM PLL Transmitter kits for educational use
Progressive Concepts : Not much on the Web, but has a great catalog and good gear !!
Smart Kit : From Greece. They have 1,4,15 and 25 W VCO Transmitters. Circuit Dias on the Net.
Simplex Kit : They re-sell Smart Kit's Voltage Controlled Oscillator based FM Transmitters.
CPEQ : FCC Compliant LPFM Stereo Transmitter for below 60$ !!
Ramsey : Complemented for his range of Radio kits, quality of documentation and marketing skills.
Mighty's Pirate Radio : aka PCS Electronics. Unique 4W PLL TX with LCD, built-in tuning circuitry.
Radio Communication Laboratory ( RCL) : Cost effective kits from India, Pre-built FM and CB Transmitters
DC Electronics : 10mW FM PLL Transmitter for US$ 50 !!!! Also BA1404 based stuff.
Rola of Aus-triee-leeeea : Resells Panaxis' kits, OEM eqpt with Panaxis incorporated, 300W RF Amp kits
DIY Electronics (Kits-r-us) : Range of 2-3 transistor transmitters, useful for beginners. Lots of other kits.
Cana Kits : Beginner's 2 transistor designs + BA1404 TX. Easy way to get hooked on the habit !!!
CIC Electronics : One and two transistor designs
Microkits : UK based manufacturer of spy surveillance transmitter kits

Readymade Exciter manufacturers + Ham kit manufacturers :
ABC Transmitters : Good Modular readymade system based on 200mW PLL + your choice of RF Amp
JT Communications : They make a PLL FM Exciter and a Stereo Generator
Infinity Communications : UK based manufacturer of FM Transmitters from 1W to 40W
TEN-TEC : Great place for 2mtr Transceiver kits. See Review
Hamtronics : Nice Commercial Quality Transceiver kits

Hands Electronics : Ham Transceivers

HOT !!!! your only chance to look at schematics before you buy !!!!

Wake up kit manufacturers : Let's have complete and verifiable Specifications / Circuit Diagrams (with only active components listed is OK) / Spectral output data on your web sites.

Visit http://www.geocities.com/Area51/Nebula/3736/ NOW !!!!

Kit Reviews :

( How about giving me your reviews on kits you built, like Alt'f , Mike and Eric did ???. I can publish your review at my site.)
Mark Wyman's Web site : with Spectral Analyses of Ramsey and Veronica kits
Articles posted on alt.radio.pirate re: the Ramsey Vs Veronica debate

My review of the Broadcast Warehouse 1W PLL Exciter with LCD 08 Aug 1998
My review of the WaveMach FMS2 PLL Exciter 20 Dec 1998
Alt'F reviews the Veronica 1W PPL Version 2
Alt'F reviews the Broadcast Warehouse DIGILOG Stereo Multiplexer Kit 08 April 1999
Alt'F reviews the Broadcast Warehouse DIGILOG Stereo Multiplexer Kit
My review of the Broadcast Warehouse DIGILOG Stereo Multiplexer Kit 13 Oct 1999
Alt'F reviews the Veronica Stereo Coder
My review of the Mighty MAX-1 FM Exciter 02 May 1999
Mike Timmer's comments on the Broadcast Warehouse High Quality Limiter Kit 20 May 1999
Eric T White's informal review of the MAX-1 FM Exciter 20 June 1999
Cana Kit's 2 transistor beginner's kit CK111 09 July 1999
DIY Electronic' 3 transistor beginner's Kit 32 09 July 1999
Cana Kit's BA1404 based Kit CK222 19 July 1999
Comments on the ROHM BH1416 Stereo Transmitter chip 26 Aug 2000
Alt 'F Radio : Ce site traite de la théorie et de la pratique de la micro-diffusion, en Anglais

Spare Parts Suppliers :
Unique Electronics : Source of electronic spare parts, Philips and Motorola transistors ....
RF Parts Company : 30 year old supplier of RF Parts for Amateur and commercial use
Donberg's Warehouse : Source of RF Components in Ireland, good source for basic Transistor specs
Circuit Specialists, Inc: RF Parts, some Kits, their "Transistors" page has basic specs and prices
NTE Electronics : Searchable database that has data sheets
Great American Electronics : Specialise in RF Transistors
RS Electronics : Large Distributors of Electronic Parts
Maplin in UK : Large Distributors of Electronic Parts
Farnell : Large Distributors of Electronic Parts

Schematics of Transmitters, Oscillators, RF Amplifiers :

Was the best source of DIY Transmitter circuits on the net
Captured the spirit of the Dutch Radio Pirates circa 1970-1980 with lots of Philips transi based circuits. His web site disappeared around 2000. As Pink Floyd would say,

Wish you were here.

Voyager Radio : Somebody just copied Pulsar's site without any credits. Useful if Pulsar's Server goes down.
Hans : Another great place for schematics, similar to Pulsar site. Hans is a helpful guy who answers e-mails.
Crystal HF : Yet another nice place for schematics. Looks like Dutch Pirates are the most technical lot !!
Schematics of Commercial Kits like Veronica, Panaxis, Ramsey, B'Warehouse...
Twilight's Schema's : Copies of SPI Kit's PLL, Stereo Coder, Limiter
Harry's Homebrew : Many circuits, incl. Bugs and small transmitters, useful info especially on winding coils
Mycal 1 & 2: Seems to know his technical stuff. It appears he corrects design flaws in Ramsey's transmitters
Technology page at Free Radio Berkeley : Some things never change, this page is one of them !
Transmitter Schematics at FRN : Good collection of other people's designs
Radioelektronicke Obvody : I knew there are some Checz Maniacs around !!
Low Power FM Broadcasting : By Dillon. FM Transmitters, J Pole design
Smart Electronics 15 W FM Transmitter PDF
Justin's Transmitter Schematics : 3-18W transmitters, Antenna, RF Amplifiers
Lar's Transmitters for the 3mtr band : Similar to Justin's site, 0.5W-25W Transmitter schematics
FM-Pirat : Similar to Justin's and Lar's site. 15W BLY88 based FM Transmitter with PCB and building instructions
YAFWT : Yet Another Fifteen Watt Transmitter based on BLY88. Easy to understand write-up, PCB designs.
Japanese Transmitter : Can transmit in English too !! Should be good for about 4-7 watts ?
Indonesian Transmitter : Can transmit in English too !! 7 and 15 W RF Amps
AMN : See how this "professional station" does it. They claim "Broadcast Quality" circuits and Antenna
Fantasy Radio : See the Schematics of the equipment used by this Dutch FM Pirate Radio Station
WARNING : Any free running VFO transmitter with less than 4 Transistors for 50-100mW output or 5 transistors at 2-5W output (ie no buffer stages, no voltage regulator for VFO) is probably highly unstable and it's frequency of operation will keep on changing with time, temperature, battery levels, antenna type, proximity of other objects to transmitter. Please build the following transmitter circuits with this warning in mind. See my review of FM Bugs for more info.
200mW 2 Km Transmitter circuit and Manual : From RCL in India
Four Transistor Transmitter
The Electronics page : Some simple FM Transmitters
Dan Evans builds the Velleman 3 Transistor FM Oscillator Kit
3 transistor FM Bug : By Harry Lythall sm0vpo
Andy's circuits : Wide Band 3 Transi and Narrow Band Xtal controlled Transmitters
2 Transistor FM Bug : PDF format file with circuit dia and good write up on operation
2 Transistor Colpitts Oscillator
Mini Oscillator and 2W Oscillator : By Kemo Kits of Germany
NoiseMantra : Based on the MicroCircuits VCO module. Better use the POS150 !!!
broadcastfm : New site started 04th April 99. Promises lots of schematics and technical stuff
One transistor FM Bug : How simple can it get ? You gotta make atleast this one work !!

Forrest Cook & Daniel Sill's Improved Stereo Modulator
SPI's Stereo Coder

Schematics of commercial CB Kits

Marconi's views on RF Schematics available on the Web : At Radio Frequencies, the PCB Design is part of the overall circuit design !!. If you find a schematic of anything over 5W at 108 MHz (or 10mW at 400 MHz) with no PCB details, just forget it !!!

Antenna, Antennae, Aerials, Rubber Duckies, J-Poles, Dipoles :
Basics of Antenna : By Linx Technologies (PDF), quick way to understand the raw basics.
The Antenna Elmer : Everything you wanted to know about Antenna. GOOD SITE
The PacketRadio Op's Antenna Handbook : Tools to design J Pole, Dipole, Quads
How to be an Antenna Guru
Antenna Practical Design : from the University of Murray, Down Under
J-Pole Antenna Design : by Mycal
J-Pole Antenna for 89 MHz : By G. Forrest Cook
Ribbon J Pole from 300 Ohm TV Cable : By Gavin Reibelt VK4ZZ
Construction of a JPole for 2m : By W. Kinsner, VE4WK
Copper Cactus Antenna : Multiple J Poles for different frequencies using the same mast
From a J to a Zepp : Excellent technical discussion on the J Pole Antenna.
Slim Jim for 3 mtr : From the FM10 Archives
Albert's 3 mtr Slim Jim
Slim Jim for 3 mtr : By Marconi, good diagrams
Slim Jim for 2 mtr : By Nadisha
Slim Jim for 2 mtr : Excellent diagram with construction details
Double Slim Jim colinear with 3dB gain over dipole : By Fred JUDD G2BCX, the inventor of the Slim Jim
6dB Colinear VHF Antenna : by Harry sm0vpo

Technical Knowledge and FAQ on RF, Pirate Radio :
How to be a Radio Pirate : A Good Technical Introduction for Newbies based on "Radio is my Bomb"
Ramsey FM10 FAQ and FM25 FAQ : By Mycal himself
Technical Guide to Radio : Another FM10 FAQ
Ramsey FM10 FAQ : Courtesy FIL
Ramsey FM10 FAQ Part II : A page from the FIL o' FAQs
Pirate Radio and TV Broadcasting Techniques : Info on Ramsey FMs, Antenna, Filters ...
(Caveat : Just because a kit is often spoken about does not mean that it is technically any good. Please read kit reviews before any purchase decisions. Use above FAQs to glean basic info on Transmitter technology only)
Beginners Guide to LPFM : FAQ of the alt.radio.pirate newsgroup

Low Power Broadcasting FAQ : From alt.radio.pirate newsgroup
Microbroadcasting - A technical Primer : By Stephen Dunifer himself. Actually not so technical, but interesting.
FM Radio communication principles : From the University of Newcastle, Down Under
Designing a 2 Transistor FM Transmitter : Francis Mc Swiggan's dissertation for his BEng course
Beginners Guide to Low Power Broadcasting : By Rick Harrison
Theory of AM, FM and FM Stereo : Basic technology explained by Steve J. Quest
Basics of Frequency Modulation : As explained by the United States Naval Academy !!!
Introduction to FM MPX : Basics of multiplexing FM Stereo signals
Structure of an FM MPX Signal : By Aztec Radio
Scott's guide to Stereo FM
Stereo for Dummies : My own look at Stereo, liberally SPICEd with waveform screen dumps. 24 Sept 1999
Scott's Guide to Broadcasting
Introduction to Telecommunications : Technical discourse on differrent modulation methods
Radio Data System ( RDS) : University of Newcastle, Australia
ARRL : Needs no introduction, I suppose

Effects of VSWR on radiated power : Might as well transmit what you are producing
Wenzel discusses SWR, Return loss and Reflection Coefficients
How far will my signal go ? : more info here and here
Technical Papers on FM Broadcasting : From Broadcast Electronics
Radio Papers Repository : Broadcast.net's large store of technical papers on Radio
How to optimise the Air Chain : From Orban
Technical Papers : From "Modulation Index", re Modulation and Loudness
Articles from RF Design Online
Application Notes : Mini-circuits explain VCOs, PLLs, Phase Noise, Test equipment and methods
Noise reduction in FM Transmitters :

FM Composite Signal Processing for FM Transmitters : By MicroCon Systems Inc.
Use your computer to feed Audio to the transmitter : Yaesutom explains the newer software available
UK Frequency Allocation tables : By the Radiocommunications Agency , London
ETSI : The European Telecommunications Standards Institute

Ham Info :
There is no denying that the Ham and Amateur community has done a lot in discovering / spreading technical information about broadcasting. The free atmosphere they had to play around in certain frequency bands fostered experimentation in VFO, Transmitters, Antenna. It also created a culture of sharing of knowledge, with many Elmers ready to assist the novices. Unfortunately , regulatory control in the 88-108 MHz band has dampened the spirit of innovation and also commercialised it. Much less free technical information is available on the Net about issues affecting the 88-108 MHz band, like propogation conditions, Antenna designs, Circuit designs, Stereo broadcasting. I am forever dipping into Ham files to see how they did things, and trying to scale it into the 3mtr band. Here then are my favourite Ham links that I would like to share with you. They reflect my current interest in Oscillators, Antenna and Xtal controlled bugs for the FM Band.

QRP Homebuider VFO Page : FET based Hartley and Clapp Oscillators
JF1FCJ's Super VXO Oscillator and experiments : Use two crystals to get larger deviations. Peter's version
Wide Range VXO : From SPRAT
Japanese Homebrew Guru JF1OZL : Wow, is this guy a diehard experimenter or what !!

Transistor Specifications :
Surface Mount Transistor FAQ : Good source re Transistor equivalents
Siemens RF Transistors : Detailed specs of Transistors, visit "search" button. GOOD SITE !!!
Transistor Spec Sheets
Low Noise Transistors : Transistor specifications
Transistor Cross Reference Database : Helps you find transistor equivalents from database of 40,000 Transistors
Pacific Semiconductor Inc. Search Page : Find out prices and very basic specs of Transistors
Military Preferred Products List : Transistor Specifications
NTE's database : Type in a generic number, get a NTE number, plug that in datasheet page to get the specs.
Transistor Specs in PDF : From the Fairchild site
Motorola data library : Lots of transistor specs in PDF
Mitsubishi RF Transistor specs : Home of the 2SC1971. Prices at RF Parts
Defpom's cross-reference and RF Transi cross-ref chart
Farnell's Database : 9500 PDFs !!

Electronics 101 :
Introduction to Electronics : The basics. Read first if you are a completely lost newbie
First Active Electronics : The very basics. Say something on the News Group only after reading this !!
Circuit Exchange : Nice site with basic Theory of Transmitters
Electronics Analysis and Design Labs : By Neil Goldsman, University of Maryland
Electric Circuits Laboratory : Duke University
Electrical Physics and Electronics : Course 9E103 at the University of Queensland, Australia
How to Bias a Bipolar Junction Transistor
Biasing RF Power Amp stages
High Frequency performance of a BJT Common-Emitter stage
Basic equations for BJTs : By Francis
How to design a FET stage
More on FETs : By Francis
What is a Varactor ? : Zetex PDF explains Variable Capacitance Diodes ( Varicaps)
How to calculate vaules of Air Coils : By Harry sm0vpo
Air Coils for VHF and UHF
Air Core Coils Calculator
Design Software for Helical Air Coils : By Saratoga Software
Calculator for basic RF Calculations : By sm0vpo
Confused about dB, dBi and dBd ?
More about the dB
Impedance Matching Network Designer
Tuned Circuit Formulae
Designing T Attenuation Pads : By Linx Technologies (PDF)
Know of a good page on Electronic Circuit Analysis and Design techniques ? Please inform me !

Electronics 501 :
Analysis of a Colpitts Oscillator
SPICE Analysis of a Colpitts Oscillator
SPICE Analyis of a 2N2222 based Colpitts Oscillator : By Dennis Erwin Thurlow
Using SPICE for RF Oscillator and Class C RF Amps : INTUSOFT suggests Sub-circuits are better than Models at RF
Micro-cap's Demo/Evaluation copy of SPICE : I didn't sleep the night I downloaded this !!!
How do I SPICE up my life for free ?
Hamcalc, RFtoolbx, Stub Tuning and other RF Software
Richard the Lion Heart designs a PLL
Japanese Hobbyist designs a Phase Rocked Roop : Lecommended leading !!
FREE DESIGN SOFTWARE AT RF GLOBALNET : Wow, Excellent design tools !!
PHILIPS RF APPLICATION NOTES : Lots of good stuff, Incl. a 250W and a 300W FM RF Amp
MOTOROLA RF APPLICATION NOTES : Lots of good stuff here by Application

Links to links :
Free Radio Network : You have gotta visit this site, many links to other great places !
Bry's Pirate Radio Links : A huge selection of links
Links to pages with Electronic Schematics
ePanorama's links to pages with Schematics
Radio links : Lottsa links, so little time
Kenneke's Links : More radio related links. Hit a page down to see them.
FIL's Links
Links to Data Sheets of Electronic Parts Manufacturers, also here
Berry's links : If you follow enough links, chances are you will land back on my page
Dealer Links : Where can I buy a thingamabob ??????
Parts, Kits and Stuff : Bunch of links for Ham kits, but could be useful for parts for FM band as well
Links page of Amazon Electronics : Links to Manufacturers, Hobbyists, Technology, FAQs
Leroy was here !!! : Excellent site with links to Electronic reference books, Parts distributors, Manufacturers ...
OCARC Ham Radio Supplier List
Pirate Radio at The Mining Company
AC6V's Links to Homebrew Antenna sites : Mostly Ham Antenna, but lots to learn !!
Ham Radio and Electronic Kits : Also by AC6V
Free Radio Stations : By Chris Smolinski
Broadcast Related Links : From the Society of Broadcast Engineers
Lara's Theme : I dont want to be associated with any link list that would want to be associated with me !!
Thailand Electronics Links : Tom Yum Chip ?
Electronics FAQ links
Infoseek > Entertainment > Radio > Technical Issues
Yahoo > News and Media > Radio > Pirate Radio
The Official Pirate Radio Kit Bulletin Board : Lots of links + a Bulletin Board to discuss TX Kits + a Technical list
FCC on microbroadcasting : Everythink I like in life can either put me in prison, make me fat or give me AIDS
Transmitters on ebay : Find loads of second-hand Transmitters, Transceivers...
alt.radio.pirate : The newsgroup to be seen at, via the Deja News service
New Hobby : Bored of FM Broadcasting, discover new vistas. Visit often as you will get a new link each time.
Guitar Amplifier Modelling : A site with technical information on Guitar Amplifier Models for use in MFX units.


11 Oct 1999

Second Opinion on that 28 Oct 1999

Yet another viewpoint ( The British are using miles again !!!) 08 May 2000


Mystereofied ?

See my article on "Stereo for Dummies" 24 Sept 1999

+ Review of the B/W DIGILOG coder 13 Oct 1999

+ Notes on NJM2035 Stereo Coder IC 20 Oct 1999

+ BA1404 BA1404, Black Chip !! 19 April 1999


Where do I begin ?
Review of simple 1-3 Transistor FM Transmitters and "Bugs"
09 June 1999






Would you buy a kit that did not have a Circuit Dia ?

I cannot believe it, but some top manufacturers still sell kits without circuit diagrams along with the kit. How do you as a hobbyist decide what to buy ? How do you understand what you are building ? How do you repair it ? How do you get parts in case some are missing ? How do you attempt mods ?

But I would rather that Circuit dias were available BEFORE you buy.
Three Cheers to
Smart Electronics for leading the way !!!

Feel strongly about this issue ? Send the manufacturer's mail !!!

Veronica always supplied dias, Smartkit always did, Wavemach always did :)
DIY Electronics has every kit's documentation PDF at web site :)
19 Sept 98 :
Broadcast Warehouse promise to supply schema with all new kits !!




Contact Information:





Wavemach Communications
320 Dixon road, Suite 302
Toronto, Ontario, CANADA
M9R-1S8, buzzer code 131
E mail



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Wavemach Communications
320 Dixon road, Suite 302
Toronto, Ontario, CANADA
M9R-1S8, buzzer code 131