FM TRANSMITTERS

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Circuit Description     + BA1404 HI-FI Stereo FM Transmitter - Simple BA1404 HI-FI Stereo FM Transmitter (88 - 108 MHz)   + BH1417 PLL Stereo Transmitter - Comes with pre-emphasis, limiter, stereo encoder, low pass filter, PLL, oscillator & RF buffer.   1 Watt RF Amplifier - Universal Class-C amplifier for low power RF Transmitters   1W portable PLL transmitter - PLL oscillator with audio limiter.   400mW VCO FM transmitter - BF199, BFR91, BFR96, varicap diode BB109.   88 - 108 MHz PLL FM TX - MC145152 PLL frequency synthesizer, MC12017 prescaler and MV2109 varicap diode.   BH1416 PLL Stereo Transmitter - Complete BH1416 (ROHM) FM transmitter with PLL, stereo encoder, limiter and low pass filter.   BH1417 Stereo PLL FM Transmitter - Frequency is selected with a DIP switch with 200KHz increments.   FM PLL 1W - 87.5MHz to 108MHz 1W PLL Transmitter   Long Range FM Transmitters -   One Transistor FM Transmitter - Transmitter uses varactor to tune the frequency, circuit is supplied with 3 Volts.   PLL FM Transmitter - PIC16F84 & MC147170 FM Transmitter. Comes with images, PCB and HEX file.   Radio Remote Control - using DTMF   Ramsey 25 BA1404 Stereo FM Transmitter - Highly praised transmitter based on BA1404 IC.   Single Chip FM Transmitter - Simple to build once chip FM Transmitter that requires only 3 - 5V to operate   TX200 High Quality 200mW FM Transmitter - uses regular NPN transistors (with optional PLL module)   TX300 300mW FM Transmitter - Uses regular NPN transistors   TX500 - 500mW FM Transmitter - uses regular NPN transistors   UHF-TV Preamplifier - Requires BFR90 transistors   Veronica 1W PLL FM Transmitter - 87.5-108MHz range with 100KHz increments   VERONICA FM Transmitter - Very stable and great sounding transmitter.   VHF Audio Video Transmitter - Uses two RF transistors

PLL SYNTHESIZERS

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Circuit Description     60 MHz - 1.3 GHz PLL Receiver with LCD - Based on PIC16F628 and TSA5511 / TSA5512 synthesizer   7.6MHz Synthesizer - Obtaining 7.6MHz from the 12MHz crystal with PIC16F84 / 4046 PLL circuit   8 Watt TX PLL with LCD - (TSA5511, PIC16F84, 4MHz Crystal)   BIAS COMS PLL transmitter - (4060, 4046, 4059, SDA2102, BB106)   CMOS RF SYNTHESIZER - Synthesizer based on available CD4059. CD4046 and CD4060 ICs.   Freddo - (PIC16F84, SAA1057, 4MHz Crystal)   Improved CMOS RF Synthesizer -   PLL FM Transceiver - TA8122N and PIC16F84 based FM PLL Transceiver   PLL Module - (TA7310P, BB105)   PLL Oscillator - (4046 PLL, CD4059 divider, CA3140 amp, 74LS112, 74LS93, LM324, CD4060, 6.4MHz)   PLL Tuning Module - (PIC16F84, SAA1057, 4MHz Crystal)   Synthesized HF Receiver -   SYNTHESIZER BASICS - Very nice intro to synthesizers by Harry Lythall

STEREO ENCODERS

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Circuit Description     + BH1415 HI FI Stereo Encoder - High-end coder with Limiter, Low Pass Filter and Muting   + BH1417 HI FI Stereo Encoder - High-end stereo coder with Limiter and Low Pass Filter   + Stereo Encoder / Multiplexer - based on NJM2035, very simple circuit and well documented   BA1404 Stereo Encoder - By Walda   BA1404 Stereo Encoder - BA1404 used as only stereo encoder.   BA1404 Stereo Encoder - With 15 KHz low pass filter.   Veronica Stereo Encoder - Uses 76KHz crystal

FM RECEIVERS

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Circuit Description     + 70 - 120MHz FM Receiver - Single chip TDA7000 FM Receiver / TV Tuner / Aircraft Receiver   27 MHz Receiver - Superregenerative receiver   27MHz / 49 MHz Walkie Talkie -   4 Transistor FM Receiver - Super regen receiver that requires only 3 Volts to operate   7MHz Receiver - The 7MHz band short wave radio which used LA1600   FM / AM Regenerative Receiver - Two transistor receiver.   FM Stereo Receiver - Based on TEA5711T and TDA7050 Integrated Circuits (by Patrick & Pedro)   HamRx - 144-146 MHz synthesized FM receiver   LA1800 FM Radio - 3V superheterodyne FM receiver   One Transistor FM Receiver - Uses MPF102 FET transistor and LM386 as an audio amplifier   PLL Stereo FM Tuner - FM radio which uses PIC micro-computer PLL system   Superregenerative FM Receiver - Superregenerative FM receiver which used 2SK241   TDA7088 Receiver - With digital tunning.

STEREO DECODERS

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Circuit Description     CA3090 Stereo Decoder - Stereo Multiplex Decoder   LM1310 FM Stereo Decoder - Converts your mono FM Receiver to Stereo   LM1800 - Stereo Demodulator   LM1800 Stereo Demodulator - Phase-Locked Loop FM Stereo Demodulator   Other Stereo Decoders - UA758, TDA7040, TDA1578, LA3370, TEA1330.   TDA1591 - Stereo Decoder

RF BUFFERS

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Circuit Description     RF Buffer Stage - One transistor buffer that can drive 2N4427 or similar power RF transistors.   RF Preamplifier - Can be used to drive higher power VHF amplifiers.

RF FILTERS

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Circuit Description     BandPass Filter - Highpass frequencies >70MHz and the low pass frequencies <180MHz.   LowPass Filter - Simple 3 coil, 4 capacitor Low Pass Filter.

POWER SUPPLIES

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Circuit Description     12 Volt 30 Amp PSU - Using multiple power transistors to increase the current of 7812 IC voltage regulator   Add-on Current Limiter - With buzzer   Electronic Fuse - Simple circuit that will protect your power supply from short circuits   iPOD - MP3 Player Charger - Portable iPod charger that you can use while away from your computer.   Lab Power Supply - 0 - 30V with current control 0.002 - 3A   Laboratory Power Supply - 1.2V - 12V with regulated current limiter through resistors   Nicad Battery Charger -   Precise Low Voltage Power Supp - With 20mA to 2A current regulation.   Variable Voltage / Current PS - Provides 1 - 28V, 0 - 3A regulation (2N3055, TIP32, 2N3053, LM1458)

REMOTE CONTROL - DTMF

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Circuit Description     2-CH RF Remote Control - Two channel FM remote transmitter / receiver that uses PIC16F84 as encoder / decoder.   8-CH IR Remote Control - Self learning 8 channel PIC16F84 based remote control receiver   AC IR Remote Control - Self learning PIC16F84 remote control receiver that can be controlled by regular IR remote control   DTMF Decoder for PC - Displays DTMF digits on your computer screen in real-time.   DTMF Radio Remote Control - 4 channel remote control.   DTMF RECEIVER - DTMF RECEIVER MT8870 TESTER   PIC Remote Control - 4 / 8 channel RF / IR remote control based on PIC16F628 and PIC16F630.   Remote Control - Simple wireless remote control unit, which was originally designed for a model hovercraft   Remote control using telephone - Switching on and off appliances through telephone line.   Simple 4-CH Remote Control - 4 channel remote control using MC145026, MC145027.

ANTENNAS

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Circuit Description     Active Antenna - An antenna with an integrated RF pre - amplifier   Antennas - Ground Pole and Half-Wave Dipole Antennas

COMPUTER RELATED

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Circuit Description     + Parallel Port Controller - Control Appliances Through a Computer   + Stepper Motor Controller - Allows you to precisely control a unipolar stepper motor through your computer   DB-15HD VGA Connector - Make your own KVM or VGA Switch   Digital Audio / Video Switch - 8 channel switch.   Printed Circuit Board Drill - Computerized PCB Mill   Simple Steering Wheel - Simple steering wheel for your PC

AUDIO CIRCUITS

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Circuit Description     4 Channel Stereo Audio Selector - Channels are digitally switched with CD4066.   Digital Volume Control - Very simple digital volume, contrast, brightness, or dimmer control   Project 3A - 60-100W Hi-Fi Power Amplifier - Excellent performance, easy to build and very relaible amplifier.   Stereo Headphone Amplifier - Simple three transistor amplifier Class AB.   TDA based Amplifier Schematics - TDA7050 amplifier requires only 3V of supply

TEST & MEASUREMENT

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Circuit Description     + Accurate Digital LC Meter - Based on PIC16F84A microcontroller, 16x1 LCD and LM311 IC   + ICL7107 - DIGITAL LED AMMETER - Measures current up to 10A with selected 100mA, 10mA and 1mA resolutions.   + ICL7107 - DIGITAL LED VOLTMETER - Measures voltages up to 199.9V with 0.1V resolution.   1 GHz Frequency Counter - Used with transmitters, receivers in VHF/UHF band (16F84, SAB6456)   10Hz - 1300MHz Frequency Meter - Universal VHF/ UHF frequency meter   20MHz Function Generator - Uses MAX038 IC to provide 0.1Hz - 20MHz frequency ranges   20MHz Function Generator 2 - MAX038 0.1Hz - 20MHz   20MHz High Speed Generator - Function Generator based on MAX038 that provides frequency output form 10 Hz to 20 MHz.   3 GHz Divide by 1000 Prescaler - Converts 0.1 - 3 GHz freqency to 0 - 3 MHz, extends frequency range measurements   3-digit Volt / Amper Meter - Based on CA3161, CA3162 ICs   8038 Function Generator - Produces sine, square and triangle waves from 20Hz to 200kH   8038 Generator - Wave type is selected with digital switch 4066 + 4017 + tactile switch   AVR Frequency Counter -   LED Oscilloscope - Uses a matrix of 100 LED as a display   LED Oscilloscope - Uses a matrix of 100 LED as a display   PIC Frequency Counter - Programmable frequency meter with PIC16F84 and UPB1505 prescaler   TV Oscilloscope Adaptor - Low frequency TV Oscilloscope   TV Oscilloscope Adaptor - 20KHz bandwith, no tv modifications are required

PRESCALERS

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Circuit Description     0.1 - 3.5GHz Prescaler -   3GHz Prescaler - 330MHz Prescaler with Preamplifier   Prescaler - Prescaler for frequency meter   Prescaler with Counter -

PIC / ATMEL / AVR

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Circuit Description     + Accurate Digital LC Meter - Based on PIC16F84A microcontroller, 16x1 LCD and LM311 IC   0 - 5V PIC Voltmeter - Higher voltage can be measured with resistor voltage divider   12 Hour Clock - PIC16F84 based, four LED display segments, 12 hour clock   4-Digit 24 Hour ON / OFF Timer - Comes with full diagrams, images, hex and asm files (translated)   AVR In-Circuit Programmer -   AVR Programmer - Ponyprog Circuit for ATMEL   AVR Programmer + Info -   Count-down timer - 16F84 timer that can count down from 1 minute to 99 minutes.   Digital Wattmeter - Digital wattmeter for transmitters with LCD display   Dual Light PIC Switch - Uses PIC12F629   Electronic Lock - PIC16F84A   JDM PIC Programmer - Allows to program PIC16F84, PIC16F628, PIC16F877, etc..   JDM Programmer Modification - Fixes problems that occur while programming PICs with internal oscillator.   LED 7 segment Count Down Alarm - PIC16F84   LED Flasher - PIC16F84 based flasher that uses eight LEDs and has five different blinking patterns.   LED Flasher 2 - PIC16F84 8-LED Flasher with three selectable patterns.   PIC 16f84 Clock - Can be used to turn off devices after specified time   PIC Frequency Voltage Meter - 50 MHz frequency counter, voltage meter & SWR/PWR indicator   PIC Pages Tutorial - Introduction to PIC microchips, includes JDM programmer   PIC Timer - 1 - 99 minutes   PIC16F628 Digital Clock Timer - Can be programmed from 1 to 59 minutes   Pony Programmers -   RCD Programmer - Built with resistors, capacitors and diodes.   Room temperature controller - Prevents room temperature going up with the heat generated by computers.   Stepper Motor controller - PIC16F84A based stepper motor controller that provides control over speed and direction.

MISCELLANEOUS CIRCUITS

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Circuit Description     LED Photodetector - Using the light-emitting diode as the photodetector   Telephone In-Use Indicator - Record your important telephone conversations.   Thermal Fan Controller - Excellent addition to your laboratory power supply   Ultrasonic Pest Repellent - Rats, mice are repelled by ultrasonic frequency in the range of 30 kHz to 50 kHz   Water Drain Pump Controller - Homemade Water Drain Pump controller

Displaying 149 Circuits