Found in the March 1989 issue of Radio Electronics magazine, this circuit is used to test printer and other cables. The indication is made by LEDs.
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...