This is a very common circuit in the days of xenon flashes for cameras. This is from a Radio Electronics magazine from November 1965. It uses an SCR and has manual triggering.
This very old circuit, from a publication from the 1970s, uses a germanium transistor and two...
In the figure we have a very sensitive touch switch circuit. A touch of the sensor causes the...
In fact, we can say that this circuit found in documentation from the 90s, consists of an intercom...