This circuit from Ferranti was released in 1969. It makes use of the company's transistors that admit current equivalents. The input voltage is 30 mV for total deflection. The band pass is 800 kHz.
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...