We found this circuit in a 1968 Electronics World. It fires a buzzer if the ignition key is turned on and the headlight is off. The circuit uses an included oscillator buzzer like the Sonalert.
In the figure we have a simple signal tracer circuit to be coupled to the volume control of an AM...
This circuit was found in documentation from the 90s, using components from that time. The...
This circuit, obtained from old documentation, allows the recovery of sulfated batteries. The...