This circuit was found in a 1965 General Electric manual. What it does is give a warning if you leave the vehicle with the headlights on or lights inside.
The oscillator of this circuit operates around 8 MHz, but the output will be at a frequency three times...
This very low current circuit with the ICM7860 was found in the April 1995 Electronics Now...
This circuit was obtained from an English magazine from 1979, but can be easily assembled today...