Electronic circuit schematics

Electronics And Projects

updated! (26/03/2014)

 

 

 

 

Light/Laser Circuits

Sound/Radio Circuits

 



Power Supply Circuits

Input Circuits




Computer circuits

 

Telephone Circuits


Other Circuits

Storage and memory

 


Alarms and security

Audio power amplfier

 

 
 
  • Audio preamp circuits

  • Microphone amplifier
  • RIAA phono amplifier
  • Low impedance microphone amplifier
  • 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
  • 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 ligh
  • 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
  • Flashing / pulsing third brake like for cars
  • Headlight flasher
  • Speed alert - wireless portable unit
  • Parking aid senses distance to rear of vehicle
  • Automatic headlight brightness switch
  • Car battery charger circuit
  • Electronic car ignition circuit
  • Car battery voltage tester using LM3914
  • Synchronized multi-spark module (SMSM) for Electronic Ignition Devices (EID)
  • Economy radar detector
  • Headlight timer
  • 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 Time
  • 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)
  • Magnetometer
  • 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
  • Remote digital thermometer sends data over AC power line
  • 4-channel data telemetry system
  • Voltage follower with 1G ohm input resistance
  • Digital compass schematic
  • Temperature datalogger
  • Serial Port A/D-converter
  • Centronics port D/A converters and low-pass filter
  • LCD Thermometer
  • 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
  • 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
  • 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
  • Flashing heart
  • Phoenix programmer
  • Funcard programmer
  • 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
  • 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
  • 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
  • Simple on-off IR photoswitch without use of comparators
  • Infrared gate (door entry alarm)
  • Infrared switch using any infrared remote control
  • Improved infrared receiver for PC with status LED
  • Infrared link for 10-BASE-T / 100-BASE-T PC network card
  • iRDA transceiver to extend IR port range up to 15 meters
  • Infrared level detector for liquid level detection and proximity detection
  • IR remote control tester
  • Infrared Transmitter and Receiver schematic diagrams
  • Pyroelectric Infrared Sensor
  • Minimal Infrared transmitter for PC
  • Simple IR transmitter circuit
  • Simple infra-red detector
  • 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
  • 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
  • RS-232 laser transceiver
  • Digital radar speedometer - laser reflexion using discrete logic
  • HeNe laser power supply
  • OPT201 Laser receiver
  • OPT301 Laser receiver
  • Laser transmitter schematics
  • Diode Laser Power Supplies
  • 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
  • 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
  • Knight rider scanning LED lights
  • 3V LED chaser using 4017
  • 6V ultra-bright LED chaser using 74HC4017
  • Led display digital Voltmeter
  • 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
  • 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)
  • 6 Channel Auto Reverse Sequential Disco Running Lights
  • Low-voltage light dimmer
  • Light chaser
  • Digi Pack DMX 512 lighting controller
  • DMX PC keyboard interface
  • 4-channel dimmer rack
  • PIC16F873 light controller
  • Digitally Addressable DALI Dimming Ballast (PDF)
  • 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
  • Pedometer
  • Simple lie detector
  • Cardiac monitor
  • Digital pedometer circuit
  • Muscular Bio-Stimulator
  • Sleeping aid based on electromagnetic-field radiation
  • Salt taster - detects the amount of salt contained in liquid foods
  • Electronic Stethoscope
  • Galvanic Skin Response (GSR) Schematic
  • Brain-Wave Machine
  • Lie detector
  • Simple lie detector
  • 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
  • MiniLOGGER V1.0
  • 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
  • Basic Stamp based altimeter
  • Interfacing EEPROM to a Basic Stamp
  • Homebrew Basic Stamp project
  • Interfacing the MAX186 8 Channel ADC to the BSII
  • Interfacing the MAX187 ADC to the BSII to measure voltages
  • RF remote control based on Basic Stamp
  • 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
  • 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)
  • Freign 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
  • PIXpand
  • 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
  • Long-period watchdog timer
  • Generate video signals in real-time using a PIC16F84
  • PIC ICD
  • Smart card programmer
  • Jupiter card programemr
  • Tutorial board for PIC16F84A microcontroller
  • 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
  • Interfacing a 4X4 keypad to a BS2 using a 74922 encoder chip
  • FSK modem with PIC16C84
  • Talking YODA project (PIC16C84)
  • PIC16F84/PIC16F87x-In-System-Programmer
  • 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
  • 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
  • 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
  • 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
  • Connecting AT90S2313 with LCD display 2x16 char and 4x4 keypad
  • 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
  • ScanMate audio activated recorded
  • PIC vacuum fluorescent display interface
  • PIC18F252 bootloader schematics
  • PIC16F876 Datalogger
  • Kodak DC-20 camera interface (PIC12C509)
  • Kodak DC-20 camera interface (PIC16F84)
  • PIC ICD in-circuit debugger circuit diagram
  • 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
     

    Misc audio (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
  • 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
  • Digital volume control
  • Electronic attenuator
  • Speech recorded using ISD2560
  • Precision audio millivoltmeter
  • Automatic loudness control
  • Three channel audio spectrum analyzer
  • Base / treble control circuit using LM1036N
  • Cuckoo sound generator
  • Room noise detector
  • 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
  • Warbler
  • 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
  • Electroscope
  • 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
  • Laboratory Control System for Cold Atom Experiments
  • Chaos generator
  • Simple BFO metal detector
  • Voltage Comparator Information And Circuits
  • 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
  • RDS Encoder
  • 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
  • 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
  • Circuit for gold wafer card
  • Keys finder
  • Electronic Eavesdropping Devices Detector
  • Lightning Detector
  • Geomagnetic field detector
  • Seismic detector interfaces to datalogger
  • Miniature magnetic gun (rail gun)
  • High voltage stun gun
  • Mini efficient magnetic coil launcher from disposable camera flash
  • 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
  • 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
  • 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
  • Electronic millipede robot
  • Downed model locator
  • Precision Receiver Battery Low Voltage Alarm
  • Launch controller for multiple rockets
  • Discharger for Receiver Battery Packs
  • RC Receiver Battery Low Voltage Alarm
  • Downed model locator Mark 2
  • 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
  • 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
  • Anti-jam system for rotary diecut machine based on PIC16F84
  • Bridge control for PLC using PIC18F84
  • 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
  • Solid-state power controller
  • High And Low Voltage Cut Off With Time Delay
  • Optically isolated stepper motor controller
  • Stepper motor controller
  • 35KHz Magnetic-Radiation Remote-Control
  • Voice activated switch using MC2830
  • Combination-controlled, fully customizable RF remote control
  • Thermoelectic controller (scriptable thermometer)
  • Stepper motor positioner
  • Stepper motor driver
  • Thermostat
  • Frequency switch
  • PIC16F84 RF remote 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
  • 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.
  • Miniature metronome
  • 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
  • Ericsson phone to PC serial port interface
  • PC serial port receiver
  • Parallel port relay interface
  • ISA 48 I/O digital card
  • 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
  • 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
  • SmartCard PC Emulator
  • Relay interface add-on board for PC
  • 8-way relay interface board for PC parallel printer port
  • Stepper motor controller for PC parallel port
  • 3-axis stepper motor controller for PC parallel port
  • PC based thermometer based on Dallas DS1621
  • Simple PC thermometer for serial port but using R/C network for measurement
  • Dallas DS1620 based USB Digital Thermometer
  • PC thermometer using PC game (joystick) port
  • iRDA interface for motherboard using Vishay TFDS4500
  • LCD2LPT with LIRC (LCD to LPT printer port) interface
  • FM radio with PC parallel port interface
  • 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
  • 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
  • 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)
  • Casio datalogger
  • 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
  • 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
  • Flyback transformer driver
  • Basic UPS Power Supply
  • Fuse monitor / alarm
  • 500W low cost 12V to 220V inverter
  • TTL power supply with crowbar protection
  • Pulse Charger for reviving tired Lead Acid batteries
  • 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
  • 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
  • Q-multiplier
  • CMOS RF PLL sythesizer
  • 3W FM Transmitter
  • Crystal radio
  • Op-Amp Radio
  • Class B series modulator
  • Advanced VHF power meter
  • The MRX-40 Mini Receiver
  • 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
  • 73MHz remote controller hallogen light
  • CB (27MHz citizens band) receiver
  • CB (27MHz citizens band) 2.5W transmitter
  • AM to FM conveter
  • 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
  • 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
  • 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
  • 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
  • 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
  • Cellular Phone calling Detector
  • Phone line in use indicator
  • Telephone music on hold interface
  • Soft musical telephone ringer
  • Telephone amplifier
  • Telephone line monitor
  • Cut telephone line detector
  • FM telephone line bug transmitter
  • Simple telephone line tap for intercepting telephone calls
  • The Link A2B+1 (the Link Telephone Intercom - DTMF version)
  • The Link 4+0 - Internal Intercom
  • The Original 2 Phone Intercom Link Design
  • 8-line intercom system using 89C51 microcontroller
  • 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
  • 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
  • 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
  • PIC16F84 based diode tester
  • Triple Stroboscope
  • Automatic heat limiter for soldering iron
  • Ultra-simple voltage probe
  • Live line detector
  • Continuity tester using transistors
  • Latching continuity tester using 4093
  • Linear Resistance Meter
  • Crystal tester
  • Capacitance meter
  • Digital voltmeter (DVM)
  • Transistor tester
  • Function generator
  • Triangle / Square wave generator
  • Picoammeter circuit schematic with 4 ranges
  • Beeper to find short circuits
  • MOSFET tester
  • Inductive meter adapter
  • Crystal tester
  • Oscilloscope testing module (Huntron circuit)
  • Voltage Monitor
  • Logic probe
  • Resistor decade box
  • Simple light sensor adapter for oscilloscope
  • Time Domain Reflectometer (TDR)
  • 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
  • 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
  • Time Delay Relay
  • Time Delay Relay
  • 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
  • Bedside lamp timer
  • Sun tanning timer
  • Digital Stopwatch 0-99sec
  • Digital Stopwatch 0-60sec
  • 28 LED clock timer
  • Photo timer circuit
  • 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)
  • 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
  • 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
  • 4 watt FM transmitter
  • FM transmitter bug
  • Small radio transmitter
  • AM transmitter
  • 2 Transistor FM Voice Transmitter
  • 15 watt FM transmitter
  • 4 watt FM transmitter
  • Tiny FM transmitter using SMD (surface mount devices)
  • Medium range transmitter circuit
  • AM FM Simultaneous Transmitter Using Digital IC (CD4001)
  • 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

    Video related scematics

  • Video Clock Superimposer
  • Video clock superimposer using PIC16C711
  • Simple AV (audio / video) wireless transmitter
  • Audio / video distribution amplifier
  • 10GHz video link
  • 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
  • RGB video digitizer
  • Color Bar Generator
  • Microcontroller test pattern generator
  • NTSC Video Distribution Amplifier
  • Commodore RF modulator
  • Video signal edge enhancement
  • Video amplifier
  • Decoder for encoded transmissions in Videocrypt and D2MAC
  • S-Video to RCA adapter
  • VGA to SCART adapter
  • Television signal amplifier
  • Video signal amplifier circuit
  • Video/Audio Wireless Transmitte
  • 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
  • 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)
  •  

    Free Decore Styles and Designs Wedding Video Vancouver Preparedness Kit electronics and projects