This circuit was taken from Maxim documentation from the 1990s. It can be implemented on the basis of modern operational amplifiers. Power supply doesn't have to be symmetrical.
This circuit was taken from a Popular Electronics from the 1990s. The circuit triggers a relay that...
The transformer inf this circuit is a 6 or 9 V unit and diodes 1N4002. The filter capacitor is 2...
This circuit causes a relay to oscillate generating a signal that turns into high voltage in a...