This traditional configuration with the 555 was obtained in an 80s Hands-On Electronics. The relay is of the sensitive type according to the supply voltage.
Found in a 1964 Electrronic Design, this circuit is intended to control analog video signals. The...
We find this microphone voice effect in 1992 documentation. The vibration of the relay contacts...
This circuit for some amps was found in a 90s Radio Electronics. The voltage can be between 6 and 25 V...