This circuit was found in an English magazine from 1977. Signal inputs and outputs must be shielded, and the circuit can be powered by battery, since its consumption is low.
Published in an old Popular Electronics, this circuit makes use of components that are still...
This stage can be used in power supplies to increase the current capability up to 10 A. The...
This circuit activates an LED, but it can be modified to activate a relay. The time is set in VR1,...