Found in a 1968 Novel Electronics Circuit, this circuit compares two light intensities using common LDRs as sensors. Transistors can be modern PNP equivalents.
We found this circuit in a 1978 publication. It is possible to detect the emission of infrared in remote...
This circuit with an optical path sensor was found in a 1995 documentation. The circuit fires...
The figure shows how to use an LM3914 with a variable range moving point. The circuit has an...