## Automatic street light

 Automatic street light

In this project, we are going to make an automatic street light easy electronic circuit. You must know that how the street lights electric circuit automatically/without any aid on in the evening and off in the morning. In this article, we are explaining an electric circuit for an automatic street light or street light controller/manager electronic project by using LDR (LDR stands for Light-dependent resistor).

Here is our latest easy electronic circuit about Automatic Street Light Managing System. In this article/project, we did not use any relay or battery for automatic on/off the circuit. We have only used a BT136 or 139 TRIAC as a relay to on and off the Street light Automatically/itself with little or no direct human control.

### Components

• TRIAC  BT134/BT136/BT139
• Resistor 220k 1/4 watts
• LDR (light dependent resistor)

### Characteristic of automatic street light circuit

• It is a very simple and high powered idea, which uses  BT136 or 139 TRIAC as a switch to switch ON and OFF the street lights spontaneously/automatically.
• It spontaneously switches ON lights when the light of the sun goes invisible (e.g in the evening)
• It automatically switches OFF illumination/lights when Sunlight falls on the LDR sensor used in this circuit.
So in this electric project/circuit, we are going to make use of a Light Dependent Resistor (LDR) as a sensor to recognize/sense the light (Especially from the sun). In the day time due to light from the sun, the resistance of LDR will be too minimal/low. So the voltage fall/drop is maximal/high. This keeps the TRIAC (BT136 or BT139) off stage. BT136 or BT139 is a TRIAC that is used to manage/control the main power 110/220volt AC directly. The light/bulb will remain OFF.

As night falls the resistance of LDR rises/increases and it turns on the TRIAC points M1 and M2. When M1 and M2 of TRIAC joint the current the light/lamp/bulb turn on. ( TRIAC is an electric component that is used to manage the light directly 110/220 volts AC main power)

### Precautionary measure

The Light Sensor Switch operates on 110/220volts AC  directly and if you are not familiar to working with mains voltage or do not have awareness/experience in working with 220v AC Mains Voltage please stay away from this electric project while it is fastened/connected with main high power voltage.

### The additional benefit of LDR switch wall lights OR Street lights

Street lights use a lot of power in rural as well as urban areas. Mostly after sunrise, the street lights remain ON. A much quantity/amount of electric energy is wasted in this way. The automatic street lights using LDR works according to the light of the sun. LDR detects the light. The light bulbs are turned ON if the light of the sun is below a particular value.

The methodology is extraordinarily sensitive. When the LDR goes dark the street lights spontaneously become ON when the LDR finds the light the wall lights OFF without any external aid i.e. automatically. Once the street lights including bulbs, tubes-lights, etc are placed in this managing system there is no need to monitor them anymore. They perform the function on its own without any external assistance. They are very cheap and reliable. This system can manage heavy loads up to 7A if you use BT139 then it can control/manage 18A main current.  The electric system can be altered to the manual mode if needed.

### Alternation in the circuit

Remember: You can also make it without using DIAC (db3). I will operate without DB3 DIAC exactly.
 Automatic street light ON OFF