The Triac trigger integrated circuit is not very common nowadays. The circuit was found in the Radio Electronics Experimenter magazine from 1989. The triac should be in accordance with the heater.
This simple version of a function generator with the XR2206 was found in the May 1977 issue of...
In a modern version this circuit can use an LED in series with a resistor in place of the lamp. The...
This VFO was found in a 1980s documentation. The central frequency is given by the crystal and the...