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  • It's Miller Time Again!

    2017-09-06 23:48:3760

    Hi Friends and neighbors. It is April and this is only my first crystal set of the year. Shame on me. I had a lot happening over the winter and my crea...

  • CD40106B CMOS Hex Schmitt Triggers Application Circuits

    2017-09-06 23:02:2760

    This is an ultrasonic parking sonar.Based on an ultrasonic amplifier from an article seen on a 1982 magazine, it was once installed on the rear bumper ...

  • Tone encoder

    2017-09-06 22:17:3860

    A basic twin-T circuit uses resistors for accurately setting the frequency of the output tones, selected by pushbutton Momentary switches produce a ton...

  • Waa-waa circuit

    2017-09-06 22:16:5961

    The waa-waa effect is achieved as certain frequencies are amplified more than others. A phase shift RC oscillator makes up the basic circuit. Negative ...

  • Whooper

    2017-09-06 21:57:0660

    Integrated circuit Ul is connected as a low-frequency asymmetrical oscillator. Its output is inverted by Ql and fed to the reset te rminal of U2 at pin...

  • Acoustic Sound Receiver

    2017-09-06 21:41:3262

    The receiver is an audio amplifier fed by SPKR1, a piezo speaker that is used as a microphone. A scope or headphone s can be used as a detector. The sc...

  • Fm demodulator

    2017-09-06 19:23:3761

    The NE564 is used as an FM demodulator. The connections for operation at 5 V and 12 V are shown in Figures 21-4A and 21-4B. The input signal is ac coup...

  • Mosquito-repelling circuit

    2017-09-06 19:17:0860

    In the 555 oscillator circuit, adjusting R2 will provide output frequencies from below 200 Hz to above 62 kHz Use a good quality miniature speaker so t...

  • Da Bandbusta Crystal Set

    2017-09-06 18:06:5160

    Hello again radio friends. Since this is my #50 radio, I thought I would make it a big one. It is much like my #35 radio that I built last year. I like...

  • Repeater beeper

    2017-09-06 18:01:1960

    The signal from COR triggers U1 which produces a beep-gate pulse that enables the analog gate Consisting of D2 and D3 to pass the beep tone generated b...

  • Atmel AT89C2051 hardware keylogers circuit with using AT89C2

    2017-09-06 16:31:3160

    Atmel On the PC keyboard PS 2 AT89C2051 keylogers circuit connection cable connects to the circuit between what is written in the wake of the program r...

  • Low-voltage-compander

    2017-09-06 14:45:2060

    The NE575 is a dual-gain control circuit designed for low voltage applications. The NE575`s channell is an expander, while channel2 can be configured e...

  • Stylus organ

    2017-09-06 14:32:1262

    IC2 is an audio frequency oscillator. Its frequency is primarily controlled by the resistance between pins 2 and 7. RV4-11 eontrol the oscillator frequ...

  • TL431C Application Circuits

    2017-09-06 14:09:3160

    In this circuit, a TL431 shunt regulator is used to sense the output voltage. The TL431 drives the LED of a 4N28 optocoupler, which provides feedback t...

  • Crystal Set - aka Roids R Us

    2017-09-06 13:43:2360

    This is my first toroidal crystal radio. I was lucky to receive some ready wound toroids in the mail the other day and I couldnt wait to build one of t...

  • How to Use a 1N5404 Diode

    2017-09-06 12:31:0660

    A diode is a simple electronic device that restricts the flow of electric current to one direction. The 1N5404 is a good example of a small, general pu...

  • Time Domain Reflectometer (TDR)

    2017-09-06 12:30:3660

    Time Domain Reflectometer (TDR) Copyright 1999-2010 Tomi Engdahl Summary of circuit features Brief description of operation: Pulse source for time doma...

  • Ne602 Direct Conversion Receiver Circuit

    2017-09-06 12:15:4671

    An NEC602 is used as a mixer with a zero IF frequency output, U2 acts as an audio amplifier. This receiver is primarily for SSB and CW signals. Tl and ...

  • SPICE Circuit Simulations for the HCNR200 and HCNR201 Analog

    2017-09-06 11:51:3172

    The purpose of this application note is to showcase the ability of PSpice software to accurately predict and simulate the behavior of Avagos HCNR200 an...

  • German Style Crystal Radio

    2017-09-06 11:27:1461

    I dont think I could call this one sexy because it looks german. My twelfth set is a distant copy of a German crystal set that I saw on an online museu...

  • 110Db Beeper Circuit

    2017-09-06 10:20:2062

    This circuit will generate an ear-splitting 110 dB from 9 V. The setup uses a single 74C14 (CD40106B) CMOS hex inverting Schmitt-trigger IC, wliich mus...

  • U2270B Application circuits

    2017-09-06 08:46:3260

    The U2270B is an IC for IDIC read/write base stations in contactless identification and immobilizer systems. The IC incorporates the energy-transfer ci...

  • Increasing Regulator Current

    2017-09-06 08:43:3361

    Description: An outboard pass transistor used to increase the current output of a voltage regulator IC. Circuit Notes Although the 78xx series of volta...

  • Connecting speaker signals to line level inputs

    2017-09-06 08:40:3461

    Sometimes it is necessary to connect a device which has only speakeroutputs to external amplifier's line level inputs. Because speakerlevels are much h...

  • Electronic Gong Circuit

    2017-09-06 08:14:1362

    The electronic gong is comprised of an oscillator (built around half of a 74COON quad 2-input NAND gate), an active twin-T filter (built around a TL081...

  • voltage frequency synthesizer PLL

    2017-09-06 07:04:2160

    The ?μA2240 consists of four basic circuit elements: (1) a time-base oscillator, (2) an eight-bit counter, (3) a control flip-flop, and (4) a voltage ...

  • STM32F103 Development Board

    2017-09-06 04:30:5560

    Product Information The STM32F103 Development Board is Base Cortex-M3 core family,uses Microcontroller 32Bit 64 Pin low power type to be permanent MCU ...

  • The ATmega32 offers a rich set of peripherals useful for thi

    2017-09-06 04:29:4860

    The ATmega32 offers a rich set of peripherals useful for this sort of project, but inevitably once you start to use those peripherals, the availability...

  • Double "D" Radio

    2017-09-06 01:14:2260

    I am taking a new direction with this radio. I have been a fan of the Crystal Radio Societys newsletter. Besides the newsletter the Crystal Queen offer...

  • Melody Circuit Circuit

    2017-09-06 00:11:0960

    A high-quality melody circuit. The slow decay waveform produced will create chime-like notes. Pitch, tempo, and duration are all adjustable. Reprinted ...

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