Photosensor circuits include a relay coil configured to control application of an alternating current (AC) power source to a load. The circuit includes a pulse width modulator circuit configured to generate a pulse width modulated signal having a pulse width that varies responsive to an average voltage across the relay coil. A photo control circuit is configured to control application of the pulse width modulated signal to a drive transistor responsive to a detected light level. A power circuit includes a rectifier circuit and a voltage divider circuit configured to generate a regulated power signal. A outputs a current responsive to a level of light detected by the phototransistor. A low pass filter circuit is coupled to a first terminal of the phototransistor filters the output current of the phototransistor to provide a light level signal voltage and a select transistor couples the pulse width modulated signal to the drive transistor responsive to the light level signal voltage having a selected level.