This circuit was obtained from a 1970s RCA. The circuit uses LDRs as sensors. The resistors depend on the A / D converter used. The circuit can be used as a shield.
Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the...
This circuit with SCR and Unijunction and which can be assembled today with modern equivalents was found in a...
This circuit was developed to find intermittent defects in an electrical control. In the event of a...