A basic one transistor regen receiver uses an MPF102 JFET to give the regenerative gain. Also uses two transistors to amplify the audio to drive an earphone. https://www.circuitbasics.com/what-are-fm-receivers/
Archive for the ‘Audio’ Category:
2024-03-29 FM Crystal Set Uses Helical Resonator For Tuning
This is a long article but a very interesting project. It uses HSMS-2850 Schottky detector diodes in a discriminator. He uses WE 1200 ohm sound powered headphones. He’s Canadian. https://electronbunker.ca/eb/FMCrystalSet.html
2024-03-24 Signal Distortion From High-K Ceramic Capacitors
A good article about signal distortion in a Butterworth low pass opamp filter using C0G and X7R MLCCs. https://www.edn.com/signal-distortion-from-high-k-ceramic-capacitors/
2024-03-08 FWBR Ripple Calculator Online
This may be helpful when choosing the amount of capacitance for a certain unregulated AC power supply – the kind that uses an old fashioned transformer. It calculates one variable given the others. https://www.chipbuilder.com/full-wave-power-supply-ripple-calculator.html
2023-11-27 RCA BFO Audio Oscillator Photos
Chuck commented about the audio oscillator being a BFO, and it reminded me that I’ve got an old RCA BFO audio oscillator stuck away in the garage. It was a cheap way of getting an audio sine wave that covered the full audio band without any switching. Nowadays it’s all done in sine and other
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2023-07-12 DC-DC Converters That Used Germanium Power Transistors
Me and my high school friend made a DC to DC converter that would give us 30 or so volts at a couple amps from a 12 volt battery. We used germanium power transistors which could not go much above 10 kHz. The Delco’s and the 2N458A’s were our favorites – we managed to push
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2022-05-08 Audio 10 Meters Over Laser Beam
I got this idea; instead of using a microphone and preamp at the end of a twisted pair, I would build a microphone, preamp and modulate a red laser with the audio and pick up the audio about ten yards away with a light detector. Notice that it runs on two 2V photovoltaic cells in
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2022-04-14 Watson’s Buzz Beeper
Watson’s Buzz Beeper I built this Buzz Beeper to find out if an audible tone could be used for sending simple commands, like turn on. Recently I built a microphone preamp with a bandpass filter that can detect my whistle. But it can be triggered by loud noise. So how about I generate a tone
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