used when the sunlight is absent it generates a set time delay before it drives ry1 and tr1 to provide power to the transformer unit in this figure sw1 is the manual power linkup the circuit can be wired as shown in fig2 the values and identifying numerals of its circuit components being set out on fig2 enabling one skilled in the art to readily construct the circuit fig4 is a detailed circuit diagram of the practical example shown in fig3 in which d c control power supply and photo sensing detection device are provided and illustrated when the device receives no more sunlight and after this is confirmed by debounce delay circuit it drives the relay ry1 to provide power to the transformer unit connected in series with the normally closed contacts ry1 and after a certain set time delay generated by timer tr0 after response to the sunlight it then drives ry1 to supply the load transformer unit with power the values of the circuit components and component identification numerals are shown in fig4 enabling one skilled in the art to construct the circuit without difficulty fig4 1 shows a wiring diagram of another embodiment the circuit component values and identification numerals being set out in the figure thereby enabling one skilled in the art to construct the circuit.