This electronic rheostat with SCR was found in the June 1964 Radio Electronics magazine. The SCR may be a modern type and the 2W potentiometer may be 470 ohms.
This is a different circuit for a component from the past, the zirconium arc lamp used in...
This circuit uses a FET to drive an LED with constante currente. The current up to 20 mA can be...
This circuit uses a phototransistor as sensor. The changes in the resistance of the transistor,...