This circuit was obtained from American documentation from 1966. It triggers when the two input voltages are within a pre-established range. The circuit can be mounted with modern transistors.
This circuit can source up to 1,000 V from a 9 V battery. Output current is very low, some...
This circuit detects the presence of strong signals from spy transmitters, enabling their...
This circuit of a publication from the 70's uses a different type of power that we had already...