This circuit is from Ferranti documentation from 1967. The operational is of the time, but the configuration is valid for modern equivalent components, including higher current capacity.
This circuit is used to cut the “click” in the loudspeaker of amplifiers when they are turned on....
Found in RCA documentation from the 1970s, this circuit is intended for firing thyristors in inverter...
In the figure we have the way to control a TIC series triac with a reed switch. The current in the...