Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime powered by a 6 V continuous voltage. The transistor can be a BD136.
The circuit is from a Radio Electronics magazine from October 1987. The Triac must be equipped with a...
The integrated circuit used is not common today and the voltage gain is unitary. The circuit is...
This source with two symmetrical output voltages was found in 90s Radio Electronics. The 22 V...