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.
In the circuit shown in the figure we have the way to excite a small speaker from a TTL output. The...
This simple circuit is from a Radio Electronics from August 1952. The current depends on the...
Found in an Electronic Design, this small power source uses a battery as a voltage reference,...