This circuit was found in an old Electronic Design. It makes use of sidacs and operational not very common today. The power supply must be symmetrical.
This photoelectric cell light relay was found in Radio Electronics magazine from April 1958. The...
The circuit shown in the figure serves as a pre-amplifier with a voltage gain of around 12 times,...
This circuit uses a lower frequency crystal in an excitation system for an oscillator with a coil...