The purpose of this circuit is to monitor the output voltage of a power supply. The under and over voltage indicator was found in the August 1991 Radio Electronics magazine.
This circuit uses an LDR as a sensor to trigger an LED indicator at a preset lighting level. The...
We found this circuit in an American publication from the 80's translated into Portuguese. The...
We found this circuit in an old French documentation from the 70s, but it can be assembled using...