This circuit allows you to read capacitances on a common analog instrument. It is part of an article in the April 1990 Radio Electronics magazine.
This full wave source uses germanium diodes, and its current is a few milliamps. We found it in an...
This circuit is from a 1968 documentation. It makes use of thermistors (NTC) to indicate...
This small transmitter has an RF amplifier stage with coupling made from the central socket of the...