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. How to Build an FM Radio Receiver
2024-04-08 The 555 Timer Chip Was Not Named After The Three 5k Resistors Inside
The 555 timer chip has been extremely popular for over 50 years. The 555 number was assigned by Hans Kamenzind; it was not named after the Three 5k Resistors. This 1 min YouTube short explains.
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
2024-03-26 HVDC Module Teardown, Operation And Explanation
A 41 min. YouTube video shows operation, tears down, and explains the components. It seems that they are made with cheap chinesium components that are too low voltage ratings so they will fail prematurely if the HVDC is left on a long time or if the spark gap is too wide. Schematic from video is
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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/
2024-03-22 The 555 Chip Under Microscope
The NE555 and some interesting information about it. A YouTube short by @Evilmonkeyzdesignz.
2024-03-15 Ferranti Argus “Hearing Aid” Computer
In the “Original Series” chapter this very interesting Wikipedia article talks about the “hearing aid computer” that used the OC-71 germanium transistors which were used in hearing aids and could go only up to 25kHz clock rate. That was quite slow – tube computers could clock at 500kHz. Later models used faster transistors and could
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2024-03-11 Flexible LED Filaments
Some information on what current and resistors to use. The LEDs are all in parallel and need about 3 Volts, current limited with a resistor. https://www.facebook.com/reel/909951727389682?mibextid=9drbnH&s=yWDuG2&fs=e