This circuit also detects IR, providing LED indication. The circuit is used to indicate humidity in bench tests. We found it in the Radio Electronics magazine of February 1990.
The components used in this 80's circuit are not common today. The circuit is very sensitive and must...
The circuit shown is for testing both signal diodes (low current) and rectifiers (high current). The...
Connected to the output of an audio amplifier or radio this circuit indicates the level of the...