This circuit is from a Radio Electronics from March 1960. The generator works with a 22.5 V battery, generating good intensity signals determined by the LC circuit.
We find this microphone voice effect in 1992 documentation. The vibration of the relay contacts...
This circuit for the car uses LDRs as sensors and does not need to be connected to the lamp. The...
Found in a Popular Electronics from the 90s, this circuit can be made with current equivalent...