Found in a 90s EDN, this circuit is indicated for power control through a 4-20 mA line. The circuit makes use of optical couplers of the time.
This circuit with optical couplers was found in General Electric documentation from the 80's. The...
This circuit is from a 90s 73 Amateur Radio Today. The circuit uses a MOSFET to provide 10 W of...
Found in the May 1988 issue of Radio Electronics magazine, this circuit is sensitive to small...