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.
This circuit provides a constant current of 1 mA, stabilized by an LED, which can be equivalent to that...
This receiver for the mid-wave band was found in a documentation from the 60's. The transistors are made...
This circuit converts a positive CMOS supply voltage to a negative one. We found it in a 90s...