Poptronics recommends this circuit for use in the car when the headlights are left on. The circuit uses a sensitive relay with contact current according to the headlights.
This timer has a divider programmed by BCD switches. The circuit is from a Radio Electronics...
Using a mechanical drive motor, this circuit was found in old documentation. The engine turned off the...
When the input voltage exceeds the value set in R4, the LED lights up, indicating this. The...