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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A year or so ago I bought a few 1W mono amplifiers from a Chinese eBay seller for cheap – see the attached photos. The only marking on the PC board is YX-1667 but I’m not sure if that’s the potentiometer or the PC board itself. . I found that if I pushed the 3.5mm
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Comment left 2020 May 29 on YouTube video in the title. This video covers MOSFET, dual gate MOSFET, JFET and BJT tuned preamps (preselectors) for his shortwave crystal radio. “The talk about using 18 volts for the cascode got me thinking about tube designs. When the plates need 100+V, and when the heater to cathode
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From FB group Building Transistor Radios For those who don’t want to or can’t use a JFET for high input impedance, you can use a regular transistor or two and bootstrapping to get a 10 Megohm high input impedance amplifier. This is from “Common Collector Amplifiers”, Electronics Now, Oct. 1993, found at americanradiohistory.com. For RFs,
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For FB group Building Transistor Radios When I started building regen receivers, the first thing I found I needed was a simple signal generator. I have a function generator, but every time I want a different frequency, I had to readjust the controls. So I built a few RF oscillators to put close to the
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Posted to FB Antique Telephones group as a reply to Kevin J. Fitzgerald I helped some students in our computer lab, and one high school kid, I think his name was Robert, was totally into phones. He had written a Basic program that printed a list out, with the various exchanges in the 714 area
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