This circuit was obtained in a 1968 manual of General Electric. The components used are of the time, but they admit equivalent. Observe the optical feedback system for control.
This circuit of a voice-controlled switch, Vox or sonic switch was obtained in a Popular...
This circuit appeared in the July 1969 issue of Radio Electronics magazine. The sensor is an LDR....
This circuit of two transistors was found in a Japanese magazine in 1967. The transistors are made...