This circuit for cars of the time was found in a Popular Electronics magazine from the 90s. The circuit is based on CMOS logic that is common even today.
This conventional astable multivibrator circuit with operational amplifier can be found elsewhere on...
Using red LEDs with ignition voltages of the order of 1.5 V we can make a multiple voltage...
This old circuit (1968) uses a germanium transistor to drive a relazy from a switch. The circuit...