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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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)
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 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
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
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
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
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
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
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
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)
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