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.
The supply can be between 4 and 10 V in this circuit and R4 is necessary when the supply is less...
This is an integrated recommended for portable amplifiers, recorders, and battery powered radios. It...
Found in American documentation, this circuit generates linear sawtooth signals using a constant...