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.
Found in 1967 General Electric documentation this circuit uses a PUT and a diac to generate 1 kHz...
Although it is a common configuration today, these circuits were taken from an old publication. The...
This simple circuit turns on a small lamp (or LED) when the light stops shining on the sensor for...