A photocell control uses a photovoltaic cell to control a switching device. These controls turn off a device when exposed to sunlight and turn on the device when sunlight is absent. Most photocell controllers work with AC or DC systems and have one or two terminal connections. A photocell with two terminal connections can be placed directly in the circuit, just like a two-terminal switch. A three-terminal photocell uses two circuits for the switching. The low-current side powers the photocell and the high-current side handles the switching of the circuit.
Cut two 1-foot black wires and one 1-foot red wire. Strip 1/2 inch of insulation off of each end of all three wires. Connect one end of the black wire to the negative terminal of the battery. Connect the other end to one of the two terminals of the photocell controller.
Take the second black wire and connect one end to the second photocell controller terminal. Connect the other end to one of the two terminals of the light or device that will be controlled.
Connect the red wire to the positive terminal of the battery and the second terminal of the device being controlled. Cover the photocell controller with a dark cloth. The light or device being controlled should be on at this time. When the photocell is exposed to light, the device should turn off.