Chapman Electric Supply, Inc. is now  part of Eckart Supply!  learn more>>

What are Photo Controls? Article

What are Photo Controls?

A photo control is one of those many devices that are encountered on a daily basis that few of us take the time to recognize for their practical significance. Turning the streetlights on when the sun starts to set or triggering the illumination of your pathway lights when you walk to your front door, photo controls can be found in industrial, commercial, and residential applications. There are a variety of electrical timers and switches available on the market, but photo controls are unique in that they use ambient light levels to trigger the power supply to light a given area. This light sensitivity makes it possible to ensure reliable lighting for only those times where it is needed – saving energy and money!

Photo controls or Photo Electric Control Units (PECUs) are light responsive switches that can be paired with traditional lighting solutions to provide automatic illumination during periods of relative darkness. The photo control switch is triggered to allow power supply when light levels fall below a specified value and then switch the supply off when the light level reaches another designated value.

The ratio between the “on” light level and the “off” light level is referred to as the switching ratio. A variety of photo control options with different switching ratios are available to service your application needs for burning hours and dimming levels.

Photo Control Components

Photo controls generally consist of a mounting piece, photocell, enclosure, relay, and the option of a color coded dome for ANSI designations. Most controls also have a built-in delay that helps to prevent false switching that could be triggered by other light sources such as vehicle headlights, lightning, flashlights, lanterns, etc.

With a wide range of needs for photo controls across many industries, there are quite a few options to choose from for your application. It is important to consider the size, environmental exposure, response time, and directional requirements for your specific use. For most photo control brands, there is a universal receptacle for the photo controls, but there are multiple mounting options available.

Chapman Electric carries a full range of options available for Tork Photo Controls.

Model Options

Turn-lock Models

turn lock photo control
  • Utility Grade
  • Quick & Delayed Response
  • Energy Saving

Flush Mounted Models

flush mount photo control
  • Weather Resistant Housing
  • Lexan Enclosed
  • Delayed Response

Conduit Mounted Models Fixed

conduit mounted photo control
  • Heavy Duty Grade Cast Zinc
  • Lexan Enclosed
  • Delayed Response

Conduit Mounted Models Swivel

conduit mounted swivel photo control
  • Heavy Duty Grade Cast Zinc
  • Lexan Enclosed
  • Delayed Response
  • 180° Swivel


  • Cadmium Sulphide, Epoxy Sealed

Mounting Orientation Options

  • Fixed Position
  • Swivel Options
  • Flush Mount Options

Enclosure Material Variations

  • Polypropylene (color coded options available from some manufacturers)
  • Clear Acrylic Window
  • Lexan®
  • Die Cast Zinc

Photo Control Applications:

Photo controls are used in a variety of different applications across industrial, commercial, and residential applications:


Providing instant response, photo controls for industrial use should comply with the latest ANSI C136.10 Standards. A few companies, such as Tork, offer locking type prong units that provide state-of-the-art reliability through re-engineering of the electromagnetic relay.

Common Applications:

  • Street & Highway Lights
  • Parking Lot Lights
  • Building Perimeter Lights


Depending on the application, there are a number of photo control options for commercial use. A swivel or stationary mounting option with a vandal and tamper resistant enclosure is a great option for security use. Business can also benefit from the savings a photo control can offer in regards to energy use and burn time for bulbs.

  • Sign lights
  • Security Lights
  • Parking Lot Lights


Photo controls are frequently put to use in residential areas for security, safety, or decorative purposes. The inexpensive photo controls offered by a number of companies allow homeowners and landlords substantial cost savings and convenience.

Common Applications:

  • Landscaping Lights
  • Fountain Lights
  • Patio or Deck Lights
  • Decorative Lights