This is the comment I left in Big Clive’s channel video. “I think this shunting current away from the LEDs is deceptive and fraudulent. They should be required to tell this in the instructions. In the US there are regulations governing vampire devices such as the AC adapters and their efficiency levels. Since they’re on
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He has a strong Aussie accent, a bit hard to understand. It’s a 28 min. YouTube video. He says BD139s have a fT of 250 MHz, but the datasheet I have does not specify any fT because the D in BD139 means they are a low frequency device, not meant for VHFs or RFs in
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Long article https://sites.google.com/site/transistorhistory/Home/us-semiconductor-manufacturers/raytheon-part-one-2 A comprehensive history of the Raytheon corporation. Also information about other companies.
This is an AM transmitter that this guy built. He says it’s rich in harmonics – it has no tuning nor low pass filtering and the stages are class C, no forward bias. It should have all the things used to minimize harmonics, like a low pass filter. Class C operation is used to maximize
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This messy bunch of parts is a 0 to 9V adjustable power supply. The original power supply board connected the two transistors in the Darlington Configuration. The unregulated 12V input goes through a 187 ohm resistor to a 10V zener diode to give a stable reference voltage. This voltage is fed to a 2.5k linear
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This 2.5 min video uses a SS8050 transistor which is not very good for a 100 MHz oscillator. https://www.facebook.com/reel/347155875050146?mibextid=9drbnH&s=yWDuG2&fs=e
The modules use both the RCWL-9616 and the BISS-0001 but it seems the schematics are all labeled BISS-0001. The parts values are different. He gives some good information about them. They operate at 3.5 and 3.98 GHz – the ones I have were advertised at 5 GHz. Also he shows his own version that uses a
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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/
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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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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