Abstract: A photoelectric load control system for applying a.c. power to a street light as a function of ambient light level includes switching means for selectively applying a.c. power to a street light for turning the street light on and off; a trigger circuit having two states, a first state which actuates the switching means to turn on the street light and a second state which actuates the switching means to turn off the street light; means for biasing the trigger circuit into one of the states; and photoelectric sensing means for varying the bias on the trigger circuit to drive it into the other state in response to the ambient light level sensed by the photoelectric sensing means.