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Archive for the ‘Amplifier’ Category:
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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2021-06-12 First Commercial Semiconductor Device
Q: What was the first commercially successful semiconductor device? Hint: It wasn’t germanium. https://en.m.wikipedia.org/wiki/Henry_Harrison_Chase_Dunwoody
2021-02-13 Speaker Made From A Steel Sheet And Audio Output Transformer
I made one of these back in 1970 or so. It was inside of a coffee can using the lid for the speaker. This class A power LED driver works good for making a speaker from an audio output transformer and any sheet of steel, even a coffee can with a steel cover. Strip the
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2020-06-23 LM386 1W Mono Amplifier Input Jack Reconfig
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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2018-08-24 2N3904 & 2N3906 for Output Transistors
From FB group Building Transistor Radios 2018-08-24 – The discussion was about the OTL complementary symmetry audio amplifier that Mr. Barnett has posted several times to the group, which uses a 2N3904 and 2N3906. Willie Barnett Let’s talk about current. Suppose your amp has a 9V supply. When the output transistor is turned fully on,
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