False triggering as a result of modest variations in the intensity of ambient light and a lack of control over switching action are two issues that are frequently encountered in conjunction with street lights. These issues can be avoided by using this straightforward controller for street lights, which features a switching circuit. The well-known op-amp IC 741 serves as the basis for the circuit's design (IC1), while the 14-bit ripple counter CD4060 serves as the basis for IC2 along with other components. IC1 and LDR1 work together to enable IC2, which then causes transistor T1 to conduct electricity. A second function of IC2 is to act as a trigger for SCR1, which then turns on the street light. When the trigger is pulled, the light is turned "off." Around its pins 9, 10, and 11, the integrated circuit CD4060 features a built-in oscillator. The master reset (MR) control is located at pin 12. When pin 12 is high, the oscillator is inoperable, but when it is low, it becomes operational again.

Circuit operation During the day, when there is light falling on LDR1, its resistance drops, and as a result, the high output at pin 6 of IC1 turns off the pnp transistor T1 and disables IC2. At this point, the SCR1 relay that turns off the street light has not yet been triggered. During the night, when there is no light falling on the LDR1, its resistance rises, and the low output pin 6 of IC1 causes the pnp transistor T1 to conduct. IC2 is then enabled, and its internal oscillator immediately begins oscillating after this. Pin 14 (Q7) of IC2 rises high at the predetermined time, which causes SCR BT169 to be triggered via resistor R9 and diode D3, respectively. Because of this, RL1 receives power, and the street light turns on. This time interval can be altered by connecting the gate of SCR1 to other pins of IC CD4060, such as pins 6, 13, etc (not shown in Fig. 1). When the output pin 3 (Q13) of IC2 gets high, the normally conducting transistor T2 is forced into non-conduction. This results in the de-energization of relay RL1, which then turns off the street light. This time can be altered by the use of the variable preset resistor VR2. To put it another way, the street light turns "on" when Q7 of IC2 gets high, and it turns "off" when Q13 goes high, provided that pin 12 of IC2 stays low.

The circuit operates on a regulated supply of 12V DC. You may assemble it on any kind of general-purpose printed circuit board and put it in a cabinet that's appropriate. When the relay is energized, the mains AC terminal for the street light is connected to the normally-open (N/O) contact of relay RL1, which causes the street light to turn on.