This circuit uses a photo-SCR or LASCR that is not a common component today. The relay depends on the load, and the power is supplied by the power grid.
This high-gain digital amplifier uses general-purpose transistors. The supply voltage is logic...
We found this circuit in the March 1993 issue of Electronis Now magazine. The circuit uses common...
Using an LDR as a sensor and an operational amplifier this circuit was found in the Encyclopedia of...