This interesting circuit found in American documentation generates a busy signal, without you having to take the phone off the hook if you do not want to answer. The components used are common.
Powered from 20 V dual power supply this circuit sources 20 W to a 4 ohm loudspeaker. The IC is...
This circuit was found in RCA documentation from the 90s. It consists of a power control for a...
This circuit shuts off and locks the power to a load in the event of a failure. The circuit is from...