This receiver for a modulated light intercom was found in a 90s Elektor. The audio amplifier can be replaced by an equivalent. The sensor can be any phototransistor.
The presented circuit makes use of two hybrid modules (see articles on the website) to drive a...
With this simple tester you can measure the gain of an NPN or PNP transistor. The instrument can...
This circuit amplifies signals only in the frequency range determined by the double T. The circuit is...