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.
Found in a 1980s documentation, this amplifier uses an integrated circuit of the era. The RLC...
This interesting experimental and didactic configuration was found in a 1977 Radio Shack...
This circuit for a frequency of 40 kHz was found in an old Electronic Design. There were no...