This circuit uses a lamp driven by the Hertz loop and measures its brightness with ordinary photovoltaic cells. The circuit is from a Radio Electronics from February 1964.
This sensitive microammeter was found in documentation from the 1980s. The accuracy of the circuit...
This circuit produces modulated tones in a loudspeaker. The effects can be adjusted by the...
We found this circuit in an old documentation from the 70s. The circuit can use any varicap and...