Friday, September 18, 2020

revisting the point contact with discrete equivalent

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We can make a Lambda Diode equivalent with two JFETs and it function much like a Tunnel Diode. We can make a SCR equivalent with two transis...
Wednesday, September 16, 2020

comparing the Ge to the Si transistor amp

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The same circuit using Ge and Si transistors. The only real difference is the 1.5 volt and 45 volt supplies. Q3 has just over 20 volt Vcc...
Tuesday, September 15, 2020

Loop stick antenna NOS and replica

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 The antique that I used as a pattern. My replica. I will add a slug and screw. Inserting the slug it varies from 100uh to 300uh.
Friday, September 11, 2020

Adjustable antenna coil from scrapsI wound a coil on the pen barrel and inserted the core.

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This post gives instructions on winding an atenna coil. http://radio.radiotrician.org/2018/05/how-to-wind-ferrite-antenna.html This is ...
Tuesday, September 8, 2020

Earbud amp using transistors from GE computer boards - 2

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I had a little shop time and made a box for the amp. I just used a piece of scrap flashing. It measured 3" X 3-1/2" that should b...

Earbud amp using transistors from GE computer boards

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I plucked some GE and TI 1960's era germanium transistors from an old computer board. This project will provide a use for 3 of them. I ...
Sunday, September 6, 2020

Using the RC filter to form a differentiator

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Take a look at the amp response from the last few post and consider this circuit. The designer is in control. You can establish the gai...