Photocell Sensor Relay Wiring Diagram and Connection

Hi, in this article, we are going to see the Photocell Sensor Relay Wiring Diagram and Connection with Light Bulb. Here, we will learn how to connect a Photocell Sensor and Photocell Relay with a power supply and lights. This will help you to make or apply this connection procedure for Automatically controlling garden or street lights based on daylight, managing indoor and outdoor lighting to save energy in commercial buildings, and automating processes that depend on ambient light conditions in industrial applications.

There are two main components in this arrangement - Photocell Sensor and Photocell Sensor Relay. A Photocell Sensor is also known as a photoresistor or light-dependent resistor (LDR). It is an electronic component that detects light levels. It changes its resistance based on the amount of light that hits its surface. In bright light, the resistance decreases, and in darkness, the resistance increases. It basically sends the signal to the Photocell Sensor Relay for automatic operation. 

On the other hand, a Photocell Sensor Relay is a device that controls relay contacts based on the signal coming from the Photocell Sensor. It turns the switch on or off electrical loads like lights. The relay acts as an electrically operated switch that can handle higher currents and voltages.

Wiring Diagram

Here, in the below wiring diagram, you can see the connection between a Photocell Relay, a Photocell Sensor, a Light Bulb, and a Power source.

Connection Description

1. The two terminals of the Photocell sensor are connected to the G1 and G2 terminals of the Photocell Relay.
2. The 230V AC power supply is connected to the A1 and A2 terminals of the Photocell Relay. The A1 terminal is connected to the Phase and the A2 terminal is connected to Neutral.
3. Now the terminal '3' is connected to the phase terminal of the power source.
4. The terminal '2' is connected to the phase terminal of the Light Bulb.
5. The neutral terminal of the light bulb is connected to the neutral terminal of the power source.

Working Principle

The Photocell Sensor continuously monitors the ambient light levels. During daylight, the sensor detects high light levels, and in darkness, it detects low light levels.

Based on the detected light level, the Photocell Sensor sends a signal to the Photocell Relay. This signal determines whether the relay should be activated (closed) or deactivated (open).

When the ambient light level is high (during the day), the Photocell Sensor sends a signal that keeps the relay in the open state. In this state, the connection between terminals '3' and '2' is open, meaning no current flows to the light bulb.

The light bulb remains off because it is not receiving power from the phase line.

When the ambient light level drops (during the night), the Photocell Sensor sends a signal to close the relay. In this closed state, terminals '3' and '2' are connected, allowing current to flow from the phase terminal of the power source through the relay to the phase terminal of the light bulb.

The light bulb turns on because it receives power from the phase line.

The neutral connection for the light bulb remains continuously connected to the neutral terminal of the power source. This ensures that when the phase connection is made through the relay, a complete circuit is formed, allowing the bulb to illuminate.

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