Are All Photocells the Same?

Photocells help reduce light pollution and save energy, but are they all the same? More and more people are using photocells in their outdoor lighting because of the many benefits that they can get. If you are wondering about photocells and if they are the same, we have shared tips and ideas below that you can refer to.

Are all photocells the same? While there are different types of photocells available in the market, the technology behind them is the same. Photocells control electric current by using semiconductors. Moreover, some photocells are adjustable so you can select the lighting level that you would like to activate the semiconductor.

What is a photocell? How do you install a photocell for your outdoor use? What are the different types of photocells? Can a photocell control multiple lights? These are some of the questions that we will discuss. Read the rest of the article below for more information.

Are all photocells the same
Image by 8786212 from Pixabay

Different Types of Photocells

The different types of photocells are photovoltaic, charge-couple devices, photoresistors, Golay cells, and photomultiplier. Let us find out more about each type below.


This type of photocell converts solar energy into electrical power. Meaning, photons knock the electrons on the cell to get higher energy that causes a current that can be used for lighting.


For this type of photocell, their resistivity to electrical currents decreases according to the amount of light that they are exposed to. Cheap photoresistors are usually used in alarms and camera light meters.

Charge-Coupled Devices

This is another type of photocell that is usually used by the scientific community as a reliable and accurate photosensor. The charge that they produce is used to analyze different things.

Golay Cell

This type of photocell is commonly used to track infrared radiation. Xenon gas is used to fill a tube that has a blackened metal plate on one end. If the blackened plate gets in touch with the infrared, it heats the gas and distorts the flexible diaphragm.


These are sensitive detectors. This is because even the faintest light wave is being multiplied by as much as 100 million times.

What Is Photocell?

Photocells are also called dusk to dawn sensors or light-dependent resistors. They are light-sensitive modules that are commonly used to find out the on and off status of lighting according to the ambient light levels. Photocells are light detectors that turn the lights on automatically at dusk and off at dawn. They are usually used in outdoor lighting. Photocells are popular because they can reduce energy consumption and also lessen light pollution.

✅ Video – What is a Photocell?

Electronhacks shared a video below on YouTube. It discusses what a photocell is. A photocell is used to detect light. Check out the video below to learn more about the topic.

How Do Photocells Work?

Photocells are made from semiconductors that are designed to respond to visible light. Meaning, when the semiconductor is exposed to a certain light level, it creates an electric current that turns off the fixture. On the other hand, when the sun sets and the surroundings turn dark, the electric current stops which turns the lighting fixture on.

Do LED Lights Need a Special Photocell?

LEDs need a different type of photocell. Take note that the standard photocells need only a small current so that they can operate during the daytime. However, LEDs run at such a low voltage which can cause flickering and interference. You can also check out this article that we have written that discusses if a photocell will work in the shade. We have shared tips and ideas that you can refer to.

Can LED Lights Flicker With Incompatible Photocell?

LED lights will flicker if it is used with an incompatible photocell. The reason for this is that the low current of the photocell interferes with the LED. If you have an LED light, make sure that you use a compatible photocell with it. You can also check out this article that we have shared titled, what causes a photocell to go bad? You can read the article for more tips and ideas.

Difference between a Solar Cell and a Photocell

The difference between a solar cell and a photocell is that a solar cell emits power for an electrical circuit while a photocell is a light-activated control switch. However, both of them need light to work.

Solar Cells

Solar cells are semiconductors. To produce a positive charge, silicon is mixed with another chemical. It is made in a single layer so that it can be able to fit the size of a single cell. Then, a different chemical is mixed with another layer of silicon to create a negative charge. This negative charge becomes the top layer of the cell. The two layers form an electrical field when light hits the cell. As a result, energy is produced.


Photocells are resistors. They measure not more than half an inch in diameter. Moreover, photocells are flat and designed with two thin solid metal wires that come out the bottom and then get soldered into a circuit board. The top surface of the cell is embedded with two fine strips of chemicals. When light hits, the two strips expand and get in contact with each other. As a result, it allows the current to pass through.

What is a Photocell Sensor?

Photocell sensors or photoeyes are usually used in automatic lighting. It is used to help sense how much ambient light there is. If the photocell detects low light levels, it turns on or off. Photocells are made up of a resistor that is attached to photosensitive plates. When more light hits the plates, the resistance changes which prompts it to turn on or off. This makes it ideal for outdoor lighting.

The good thing about using photocell is that there is no user input needed. Hence, you do not have to worry about turning the light on or off. The photocell is also referred to as a photoelectric switch because it works similarly to a light switch.

How to Install a Photocell Sensor for Outdoor Use

To install a photocell sensor for outdoor use, there are important steps that you need to follow which include turning off the circuit breaker, dissembling the housing that contains the exterior lights, connecting the wires, and testing the photocell. Because this task requires handling wires, you should hire the services of a professional electrician if you are not confident with your wiring skills. Let us learn more about the steps below.

Turn Off Circuit Breaker

The first thing that you need to do is to turn off the circuit breaker to the outdoor light that you are working on. The power must be cut off before you work on it.

Disassemble Housing

The next step is to disassemble the housing where the exterior light is located. You can record or take a photo of how you disassemble the housing so you can easily put it back together.

Work with the Wires

 There are two black wires on a photocell that should be tapped into the black wire that runs between the light fixture and the main power. Disconnect the black wire from the main power. Next, connect one black wire on the photocell to the black wire that is connected to the house. Connect the second black wire on the photocell to the black wire on the light fixture. Secure the wires properly.

Check the Connection

Make sure that you cover the new connections with electrical caps that are tightly set around the wires. Next, tape the connections using electrical tape. There should be no exposed copper wires.

Test the Photocell

The next step is to test the photocell by turning the power back on. Turn the switch into the on position then cover the photocell with your hand. If it turns on, it should be working properly.

What Causes a Photocell to Go Bad?

Many issues can cause a photocell to go bad. One reason for a photocell to go bad is because it functions incorrectly. Another reason is that there is loose wiring between the photocell and the main circuit. Make sure that you properly determine the issue so that you can fix it. If you are not familiar with working with photocells or lighting fixtures, you should hire the services of a professional. Read this article titled, why do photocells face north? We have shared tips and ideas on where to properly place photocells. 

Do Photocells Wear Out?

Photocells do not wear out. They are sensors that detect light, are inexpensive, use low power, and are easy to use. Photocells are often used in gadgets and appliances. You can also check out this article that we have written titled, why does my dusk to dawn light stay on all day? We have shared an in-depth discussion about the topic.

Can a Photocell Control Multiple Lights?

A photocell can control multiple lights as long as they are on the same line. It works like a switch that can turn on and off multiple lights. As the photocell detects light, it switches off the lighting fixture. On the other hand, it turns on the fixture when it is not able to detect light. We have also shared this article that discusses if one photocell can control multiple lights. Check out the article for more information.


You have reached the end of this article that discusses if all photocells are the same. We have found out that while there are different types of photocells in the market but the technology behind them is all the same. We have also discussed the different types of photocells. Make sure that you choose the right photocell for your lighting fixture. Thank you for reading!

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