2B-ELECTRONIC STREET LIGHT SWITCH
THE SPECIALITIES OF PROJECT
This is a very simple and useful project. With the help of this project we can put street light ON in the night and OFF in the morning. This is done by automatic switch. No operator is required for the street light and electricity consumption is also saved.
TECHNICAL DESCRIPTION AND WORKING OF THE PROJECT
This project has been developed and tested by our readers and sent to the “T.V.Engineers Technical lab” for publication in the book. The spare parts and PCB of the projects published in the series of our book publication or available in the market. The information of project code is given in the first and last page of the books.
LDR is the main part of this project. When sunlight falls on the LDR the resistance of the LDR goes low and in the dark it goes high. With the help of this project the street light can be put ON/OFF automatically. The project can be divided into two parts:
- Power supply
As per diagram when ON/OFF switch S1 is pressed then through diode and resistance R1(10K) converts AC into DC. From zeener diode ZD1 we get 9.1V DC. It is filtered through the capacitor C1 0.1mfd and C2 1000mfd.
The switching section of the circuit is made of LDR, IC555, Transistor T1(BC548), T2(BC548) and T3(2N2222). In the circuit timer IC555 works as a inverter. The input of the IC at Pin No.2 is low and output Pin No.3 is high. Through the high output the triac MT1 conducts and bulb connected with this glows. When in day time light falls on LDR the T1 and T2 transistors remains in cut-off position the transistor T3 also remains in cut-off position. In this condition the IC555 does not conduct. The triac connected in the output of IC also does not conduct and bulb does not glow. In the night there is no sun light, the Pin No.2 of IC get triggered and bulb connected to the output of IC gets ON. The LDR is kept at such a place where light falls in day time.
PRECAUTION WHILE MKING THE PROJECT
- After giving AC voltage to the circuit don’t touch the circuit.
- While soldering take care of triac’s pin.
- Use IC base for IC.
Check all parts and then make connections for the circuit.