Alarms and security related

·  Ultrasonic remote control & alarm system

·  Door knob alarm (PDF)

·  Water seepage alarm (PDF)

·  Micro-power over temperature alarm (PDF)

·  5 Zone alarm circuit

·  Miniature loop alarm

·  Gate alarm circuit

·  Perimeter monitor

·  Digital combination lock

·  Touch activated alarm system  

Audio filters

·  3KHz low-pass filter plus audio amp (PDF)

·  "A" Weighting Filter For Audio Measurements

·  Multiple Feedback Bandpass Filter

·  Akerberg-Mossberg (AM) Second Order Bandpass inverting

·  Deliyannis Second Order Bandpass I inverting

·  Deliyannis Second Order Bandpass II inverting

·  KHN (Non-Inverting Input) Second Order Bandpass inverting

·  Multiple Feedback (MFB) Second Order Bandpass I inverting

·  Multiple Feedback (MFB) Second Order Bandpass II inverting

·  Tow-Thomas (TT) Second Order Bandpass inverting

·  Twin-T Second Order Bandpass inverting

·  Berka-Herpy (BH) Second Order Bandpass non-inverting

·  Fliege Second Order Bandpass non-inverting

·  KHN (Inverting Input) Second Order Bandpass non-inverting

·  Mikhael-Bhattacharyya (MB) Second Order Bandpass non-inverting

·  Sallen-Key (SK) Second Order Bandpass non-inverting

·  Akerberg-Mossberg (AM) Second Order Notch inverting

·  KHN (Non-Inverting Input) Second Order Notch inverting

·  Berka-Herpy (BH) Second Order Notch non-inverting

·  Fliege Second Order Notch non-inverting

·  KHN (Non-Inverting Input) Second Order Notch inverting

·  Mikhael-Bhattacharyya (MB) Second Order Notch non-inverting

·  Sallen-Key (SK) Second Order Notch non-inverting

·  Twin-T Second Order Notch I non-inverting

·  Twin-T Second Order Notch II non-inverting

·  First Order Highpass III inverting

·  First Order Highpass IV inverting

·  First Order Highpass I non-inverting

·  First Order Highpass II non-inverting

·  Akerberg-Mossberg (AM) Second Order Highpass inverting

·  KHN (Inverting Input) Second Order Highpass inverting

·  Multiple Feedback (MFB) Second Order Highpass inverting

·  Berka-Herpy (BH) Second Order Highpass non-inverting

·  Fliege Second Order Highpass non-inverting

·  KHN (Non-Inverting Input) Second Order Highpass non-inverting

·  Mikhael-Bhattacharyya (MB) Second Order Highpass non-inverting

·  Sallen-Key (SK) Second Order Highpass I non-inverting

·  Sallen-Key (SK) Second Order Highpass II non-inverting

·  Twin-T Second Order Highpass non-inverting

·  First Order Lowpass III inverting

·  First Order Lowpass I non-inverting

·  First Order Lowpass II non-inverting

·  Akerberg-Mossberg (AM) Second Order Lowpass inverting

·  KHN (Inverting Input) Second Order Lowpass inverting

·  Multiple Feedback (MFB) Second Order Lowpass I inverting

·  Multiple Feedback (MFB) Second Order Lowpass II inverting

·  Bach Second Order Lowpass non-inverting

·  Berka-Herpy (BH) Second Order Lowpass non-inverting

·  Fliege Second Order Lowpass non-inverting

·  KHN (Non-Inverting Input) Second Order Lowpass non-inverting

·  Mikhael-Bhattacharyya (MB) Second Order Lowpass non-inverting

·  Sallen-Key (SK) Second order Lowpass I non-inverting

·  Tow-Thomas (TT) Second Order Lowpass non-inverting

·  Twin-T Second Order Lowpass non-inverting  

Audio power amplifiers

·  8 watt audio amp

·  20W Amplifier

·  50W Amplifier

·  100W RMS Amplifier

·  2-Channel Power Amplifier

·  Push-Pull Class A Amp using type 5687 dual triodes

·  Push-Pull Class A 2A3 Stereo Amp

·  Single Ended Class A2 SV811-10 Stereo Amp

·  Audio amplifier output relay delay

·  HeadBanger Headphone Amp

·  2W Amplifier

·  TDA2030 8 Watt amplifier

·  16 Watt amplifier

·  8 Watt amplifier

·  20 Watt Class-A Power Amplifier

·  El-Cheapo - A Really Simple Power Amplifier

·  Single Chip 50 Watt / 8 Ohm Power Amplifier

·  Hi-Fi Headphone Amplifier

·  100W Guitar Amplifier

·  Death of Zen (DoZ) - A New Class-A Power Amp

·  Soft-Start Circuit For Power Amps

·  Thermo-Fan To Keep Your Amp Cool

·  Audio Amp Output Power Limiter

·  55W (Originally 75W) Power Amplifier

·  300W Subwoofer Power Amplifier

·  20 Watt / Channel Stereo Power Amplifier  

Audio preamp circuits

·  Simple microphone preamplifier

·  Phono Preamp

·  Simple microphone preamplifier

·  ECM Mic preamp

·  Hi Fi preamp

·  Electret mic amplifier

·  Audio preamplifier

·  Audio preamp  

Automative, car and motorcycle

·  Portable CD Player Adapter For Car

·  Car battery charger

·  Wireless Auto Tachometer

·  Headlight reminder  

Data acquisition and data logging

·  Analog input section based on AD9220

·  Honey Bee counter (PDF)

·  Capacitance type liquid level measurement (PDF)

·  Serial Port A/D-converter

·  Centronics port D/A converters and low-pass filter

·  Water-level sensor  

Games and fun stuff

·  Pine Racecar Victory Judge

·  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

·  DIT shutterglasses controller  

Infrared based schematics

·  IR remote control

·  40KHz light receiver (PDF)

·  40KHz TV-VCR repeater (PDF)

·  Infrared remote transponder

·  Build an Infrared night scope

·  Decoding IR Remote Controls

·  IR detector

·  PC IR Remote Control

·  Pyroelectric Infrared Sensor

·  Simple IR transmitter circuit

·  Simple infra-red detector

·  IR remote control extender

·  IR remote control tester

·  40khz IR Tester

·  555 timer 40khz IR Oscillator

·  IR detector / emitter

·  Cheap 40KHz clock

·  Stable 40KHz clock

·  Serial driven IR remote control

·  IR remote transponder  

Laser related power supplies and data transmission

·  Laser power supply

·  Laser transmitter/receiver

·  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)

·  Experimental laser data link

LED related schematics 

·  LED chaser

·  7 Segment LED Counter

·  1.5V LED flasher B (PDF)

·  Low current LED flasher (PDF)

·  1.5V LED flasher A (PDF)

·  Flashing LED advertising badge (PDF)

·  Pulsed LED test circuit (PDF)

·  Low battery voltage flasher (PDF)

·  Adjustable flashing LED

·  LED Mood Light

·  LED Audio VU Meter

·  LM3909 LED flasher


·  TRIAC light dimmer

·  12VDC Fluorescent Lamp Driver

·  Strobe light

·  Adjustable Strobe Light

·  5W Fluorescent light intensity modulator (PDF)

·  1W Fluorescent lamp night light (PDF)

·  Electronic night light

·  LED Mood Light

·  LX-800 Lighting system

·  Xenon Strobe Light

·  Lamp flasher/dimmer

Medical and health related

·  Simple lie detector

·  The ESP SIM (Sound Impairment Monitor)

Microcontroller based

·  AT89C2051/4051scanning 7-segment display and keypad

·  AT89C2051/4051 Driving dot LED

·  AT89C2051/4051stepper motor interface

·  AT89C2051/4051connecting dumb terminal

·  Simple RS232C Level Converter using Transistors

·  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

·  Atmel 89C Series Flash Microcontroller Programmer

·  AT89C2051 real-time controller

·  PIC12C508 Night-light saver

·  AT89C2051 Night light saver

·  Atmel 8051 Flash Based-Microcontroller Programmer

·  AT89C2051 Digital thermometer and clock

·  Build a PIC controlled DDS VFO, 0 to 6 MHz

·  PIC controlled DDS VFO, 0 to 6 MHz

·  PIC16F84 line following robot

·  50 MHz frequency counter, voltage meter & SWR/PWR indicator

·  PIXpand

·  Serial to parallel converter using the AT89C2051

·  AT89C2051 serial COMs to LED driver

·  101 AT Keyboard to ASCII Decoder using 68HC705J1A MCU

·  A Scenix (and PIC) Programmer

·  Long-period watchdog timer

·  PIC Project #1 - RS232 to I2C Interface

·  Dual PIC16C84 prototype board

·  Talking YODA project (PIC16C84)

·  2-wire LCD interface using PIC16CF84

·  PIC16F84 Serial I/O-expander with PicBasic

·  Picxie 2 - 8x8 Animated LED Signboard (PIC16F84) Picxie 2 - 8x8 Animated LED Signboard

Misc audio (also see Music, Amplifiers, Preamp)

·  Old-fashioned siren effect

·  Simple VOX circuit

·  Analog VU meter

·  Voltage controlled amplifier

·  Audio graphic equaliser

·  Intercom preamp

·  FET audio mixer

·  Microphone mixer

·  Tone control

·  Digital volume control

·  Sound level meter

·  Very loud beeper (PDF)

·  Digital noise generator (PDF)

·  Condenser microphone hookup

·  Phase shifter

·  Paradoxical Sound Syntheizer

·  Audio line isolator

·  Dynamic microphone to electret microphone input

·  Use amplifier phono input as line level input

·  Speaker signals to line level inputs

·  Sine wave generator

·  3-Band equalizer

·  6-Input mixer

·  Doorphone intercom

·  Stereo line driver

·  Audio notch filer

·  Peak reading audio level meter

·  Tone control

·  Electronic canary

·  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

Miscellaneous schematics

·  Simple BFO metal detector

·  Random noise generator

·  Analog pulse counter

·  Analog opto-isolator

·  Pulse width modulators (PWM)

·  Pulse width to voltage converter

·  Fantastic Atom Expander

·  Black Light

·  Flash slave trigger

·  Ion detector

·  Ultrasonic transducer oscillator circuit

·  Fogger smoke machine

·  Electric field disturbance monitor

·  Dual comparator forms temperature-compensated proximity detector

·  Electromagnetic field detector

·  Ultrasonic dog whistle

·  An Inexpensive X-ray Machine

·  Ultrasonic switch

·  Very basic circuits

·  Bat detector

·  FCTS Project

·  Morse Code Beacon Keyer

·  Lightning Activated Camera Shutter Trigger

·  Morse Code Practice Keyer 1

·  Morse Code Practice Keyer 2

·  741 Light Sensor

·  Fluid level detector t  

Power Circuits

Bowden's Hobby Circuits

·  0-10V control for RC servos

·  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

·  Two tone train horn

·  Radio Control Battery Backup

·  Current loop interface

·  Switching solenoid driver

·  Modular relay system

·  Light/dark detector

·  Pulse Width Modulation DC Motor Control

·  Stepper motor controller

·  Temperature monitor

·  Cold activated switch

·  Voltage comparator switch

·  Dark activated switch

·  DC Push Button Motor Control Circuit

·  Light detector

·  Sound operated switch


·  Constant Temperature Circuit

·  PWM DC Motor Speed Control

·  Solenoid starter

·  CO2 controller for planted tanks

·  Light activated relay

·  Octave screamer

·  Optical Theremin - electronic musical instrument

·  Simple colour organ

·  Guitar fuzz effect

·  8 note tune player

·  Colour (Sound) Organ

·  Transisor organ

·  Simple line mixer

·  Simple MIDI tester

·  Electronic metronome

·  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

·  Linux Infra-red Remote Control (LIRC)

·  Compter microphone

·  Laptop Computer Serial Port Power Booster

·  Power supply provides +5VDC regulated, +10VDC unregulated and 7.5VAC

·  A Bench PSU (0-15v 0-3A)

·  6V to 12V Converter

·  Tesla coil / HV generator

·  12VDC To 120VAC Inverter

·  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

·  Negative voltage generator

·  Power reminder beeper (PDF)

·  Unplugged power cord alarm

·  Machine power loss beepter (PDF)

·  HV supply: 12VDC in, 12KV out

·  Generating -5VDC from +5VDC

·  Filtering PC bus POWER

·  Adjustable power supply using LM317

·  Simple +5V power supply circuit

·  12V 30A power supply

·  Dual regulated power supply

·  Fuse blown indicator

·  Gyrator circuit

·  Variable power supply

·  Nicad battery charger

·  Regulated 12V supply

·  Unregulated power supply

·  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

·  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

·  Charger for gel lead acid batteries




·  Crystal radio  

   QRPp DSB transceiver for the 80 meter band (1 Watt P.E.P.).




   40 meter transceiver w6bky

   Kajman 80m SSB 2W


  Montaje del kajman para la banda de 40m realizado por EB1DGC

  Caculadora online para realizar filtros pasabanda



   Maritaca QRP DSB CW para 40m.

  Transceiver DSB for 80, 40 or 20 Meter IC-TCA440

   El BUSGOSU QRP para 40m SSB - EA1AYN -

   Proyectos QRP de IK3OIL

   Frecuencimetro dial LCD

   Frecuencimetro con Pic

  Emetteur-récepteur BLU et CW (20, 40 ou 80m)...

  Emetteur-récepteur BLU miniature 40m, le Forty





                       Accede a los equipos qrp de F6BCU   

Descarga el "Handbook version 2017" de F6BCU
1 fichero de 613MB


                  HF SDR(Software Defined Radio) transceivers      

            Todos los diseños publicadoss y materiales son gratuitos para uso personal y no uso comercial. Otro uso para fines comerciales no están permitidos sin el permiso del autor.


    BiTX  QRP Kits  SSB      

    TECHNICAL INFORMATION FOR HAMS  Información técnica que no te puedes perder

  Transmisores para Radiodifusión





  Medidor de ROE y potencia digital

  YC3LSB informacion QRP , MUY interesante


  QRP 2w AM

  PLL - digital tuning FM 88-108 MHZ

  Tualatin 40m Superheterodyne Transceiver

   Santiam 40m DC Transceiver

  QRP Power Meter

  Preamplficador de micro

   Analizador de antena

  QRP 80m DSB

   RX 80m SSB - CW

   TX 40m

   QRP 40m DSB

   RX 40m ssb conversion directa

  Transverter 10-40m conmutacion electronica

  QRP Transmitter Projects

Bowden's Hobby Circuits  

·  Automatic message sender for CB

·  RF Sensing relay driver

·  Vibrating pocket bug detector


·  Op-Amp Radio

·  Bug detector

·  175KHz inductive pulse receiver (PDF)

·  200-400 MHz voltage controlled oscillator PDF

·  AM/FM/SW active antenna

·  RF Sniffer <.5 to >500 MHz

·  Receiver

·  Smooth Tone Clickless CW Sidetone Generator

·  Variety of receiver converter projects

·  One transistor FM receiver

·  50MHz Assistant (Preamp & Power Amp.)

·  Bug detector

·  Basic RF oscillator  


Zetagi BV-131 para 40m 




       LOOP MAGNETICO gamme 10/80 metri 3,5-10 Mhz

      Antena HF caña de pescar

     F5AD la web de las antenas para radioaficionados que no debes perder de visitar





·  AA battery solar charger

·  Solar Panel Charge Controller / Low Voltage Disconnect Circuit

·  Solar Panel Current Meter

·  Solar Charged LED Flashlight

·  AA battery solar charger

·  Solar Panel Charge Controller / Low Voltage Disconnect Circuit

·  Solar Panel Current Meter

·  Solar cell Nicad charger


·  Ringing Phone Light Flasher

·  Phone Busy Indicator

·  FM Telephone Bug

·  Cut Phone Line Detector

·  Simple Phone Tap

·  Telephone Hold Button

·  Telephone Recorder

·  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

·  Telephone privacy adapter

·  Telephone ringing circuits

·  Simple circuit to connect telephone equipment to audio mixer

·  Hands-free telephone

·  Using old phones as an intercom

·  Phone line to audio

·  Phone recorder

·  Telephone tap

·  Telephone controlled night light


·  Tri-Waveform Generator

·  JFET crystal testing oscillator

·  Electric field & leakage detector

·  Simple polarity detector

·  RCM710 Electronic Scale

·  LASER/LED light output intensity meter (PDF)

·  Frequency and capacitance meter

·  Simple light sensor adapter for oscilloscope

·  Time Domain Reflectometer (TDR)

·  EMF field probe

·  Function generator

·  Logic probe

·  Zener diode tester

·  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

·  Build a Magnetic Field Immunity Tester

·  555 Timer IC Tester

·  Continuity tester 2

·  Continuity tester

·  Logic probe

·  Time Delay Relay

·  Time Delay Relay

·  Line powered 60Hz clock generator (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

·  Push Button Switch Debouncer

·  Square wave oscillator

·  Clock generator


·  Spark-gap transmitter

·  Wireless microphone

·  A 3m (100 MHz) small bug

·  FM transmitter

·  Small Radio Transmitter

·  FM Telephone 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

·  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


·  Audio / video distribution amplifier

·  Driver for multiple VGA monitors

·  Closed-Caption Decoder

·  PIC-Tock video clock

·  Video signal edge enhancement

·  Video amplifier

·  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

           Regulador 12V - 20A para energia solar fotovoltaica      

  Descripción de Kicad 

                    Kicad es un programa de código libre (GPL) software para la creación de esquemas electrónicos y circuitos impresos.