This circuit reminds the driver when he removes the keys from the ignition, leaving the lights on. The circuit is from an August 1974 Radio Electronics magazine.
This circuit can operate with signals up to 60 MHz using the indicated operational. We found it in...
This circuit takes advantage of the noise generated at the reverse biased junction of a germanium...
Equivalent transistors can be used on this 80's circuit. Any general purpose PNP transistor can work...