Photoelectric Sensors and the Power of Light

Electronics and Electrical

When you turn on your coffee pot in the morning, power is sent from huge generators across high tension cables, to a transformer and then to your house. However, there are other ways to create electricity and photoelectric sensors create power with light. This type of energy sees a great deal of use in industry as well as the home but how does it work? Let’s look a little closer and see.

The Photoelectric Effect

What does photoelectric mean? It basically means getting electrical power from light. But can light really be changed to another form of energy? The answer is yes. Energy cannot be created nor destroyed but it can be changed from one form to another.

Here is the basic principle of photo electricity. If you shine a beam of light on a piece of metal, the energy from the light is enough to displace some of the electrons from the metal’s atoms (essentially creating electricity). This was first clarified by Albert Einstein in the early 20th Century.

Photoelectric sensors sense light and the absence of light. They have a transmitting component and a receiving component. The transmitter sends a constant beam of ultraviolet light to the receiver. This is like connecting an electrical wire between transmitter and sender. If something gets in between the two, the circuit is broken. This technology can be used to either start or stop electrical powered equipment, or send a signal.

Types of Photoelectric Sensors

There are three basic types:

  • Through beam – accurate and reliable. Can sense light from a long distance. These systems must have a transmitter and receiver.
  • Diffuse – most cost effective option. Only requires one point of installation.
  • Reflective – requires both reflector and sensor. Not as accurate as through beam methods.

Here is a how a typical through beam setup would function in an industrial environment. You have a conveyor belt with material in cardboard boxes. As each box passes in front of the photo cell, it breaks the beam between transmitter and receiver and triggers a sealing mechanism with hot glue.

In another scenario, a photo cell unit can be set up at the end of a conveyor system. As materials travel to the end, they block light to the photo cell receiver and this is used to stop the conveyor so the materials do not spill. They can then be removed from the conveyor and more materials can travel to the end. These are only two of many uses for photoelectric technology today.

Finding the Best Source for Photoelectric Sensors

When you need the best photoelectric sensors for your business, go with a supplier who can furnish all your needs. Also, look for a company offering top name brand selections at affordable prices.