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.
The circuit shown is from the Motorola Linear Databook from 1990. The circuit has two outputs with...
Suggested by General Electric in 1965 documentation, this circuit controls the current at a load...
This filter for the scratching noise common in record players was found in Radio Electronics from the...