Found in a 90s Popular Electronics, this circuit checks if a remote-control transmitter is emitting signals. The sensor is a general-purpose type found in many electronic devices.
We found this circuit in an old English publication. Transistors are general purpose and the block...
This simple circuit was found in the Spanish magazine “Todo Electronica”, in an edition of 1996....
This circuit operates at a voltage of 1.3 V from a single mercury cell. We found in an old...