We found this circuit in a Japanese 1968’s documentation. The circuit makes use of transistors from that country common at the time of publication. Observe the symmetrical power supply for the circuit.
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...