This interesting circuit converts BCD signals into a voltage that can be used in an analog application. The circuit was found in the July 1991 issue of 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...