Originally indicated as an alarm alert in a 1990s US publication, this circuit can be used as a shield to control a strobe lamp. The sensor is a optocoupler with LDR.
This VCO makes use of components from the 1980s. The circuit can be implemented with modern...
This circuit uses an LDR as a sensor to trigger an LED indicator at a preset lighting level. The...
This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms...