This circuit triggers a relay when a light beam that hits the phototransistor is cut off. The circuit is from Electronics Now and the supply voltage depends on the relay voltage.
The purpose of this 1967 Philips circuit is to produce a rectangular signal from a sharp pulse....
This circuit allows you to read capacitances on a common analog instrument. It is part of an...
The idea of this circuit is to use an AM radio with headphones to receive sound signals...