This circuit was obtained from Electronics Now magazine, July 1995. The triac depends on the heating element current, and the sensor will determine the adjustment potentiometer.
This amplifier was found in a Japanese publication in 1972. Transistors are uncommon today, and...
The current of this source is 200 mA at the most, and the output depends on the zener that may...
Found in Mallory documentation from 1968 this circuit uses an integrated circuit from that time. The...