This circuit was found in a 1967 General Electric manual. It shows a SCR control with unijunction and zener diode. The triac depends on the controlled load.
This low drift or offset circuit is from an 80's documentation. The configuration can be made with...
This circuit has a logarithmic response as a function of the light falling on the sensor. The...
Found in 80's Electronic Engineering, this circuit can tune the frequency to be rejected. The power...