This circuit is from 1967 General Electric documentation. It uses SUS which are not very common components today. The maximum frequency should not exceed a few kilohertz.
This circuit makes use of an optical coupler to isolate the telephone line. The circuit is from...
This circuit was found in na old latin american magazine. The circuit uses two germanium...
A complete test for opto-couplers can be made using the circuit Bellow. The function generator...