This circuit was found in a 1965 General Electric manual. What it does is give a warning if you leave the vehicle with the headlights on or lights inside.
This old receiver (1967) uses germanium transistors from the time and coupling transformers,...
This circuit can act as a shield being controlled by a microcontroller by pin 1 or 2. The...
A negative pulse applied to the input of the circuit shown in figure bellow turns on the relay....