This 1970s RCA circuit can be triggered by light or dark, depending on how the LDR is connected. The controlled load depends on the triac.
This switching circuit for analog signals is from a 90’s Electronic Engineering. The components...
This circuit triggers a relay when a pulse of light hits the LDR. The potentiometer serves as a...
This circuit acts as a VU-meter when connected at the output of any audio amplifier, triggering a...