Light Sensors Key Terms

Understand the basic terminology relating to light sensors

By Howard Robertson

Light sensors are useful for detecting light or brightness in a manner similar to a human eye. These sensors allow the settings to be adjusted automatically in response to the changing ambient light conditions. A light sensor is an important component in various devices, such as industrial lighting systems, consumer electronics products and automotive systems.

While interacting with the suppliers of light sensors, you will come across various technical terms that indicate types, technologies and properties of sensor devices. Understanding these light sensors key terms will help you make smarter business choices. This guide covers some common terms that you will hear from the light sensors dealers, including photodiode, illuminance, photoelectric sensors and photocells.

Photodiode

A photodiode is a semiconductor light sensor that detects the presence of light and converts it into either current or voltage, depending upon the mode of operation.
Try: You can get technical information about photodiodes at Hamamatsu Corporation, a manufacturer of light sensor devices.

Illuminance

Illuminance is the measure of intensity of light incident on a surface; it can be correlated to the brightness perceived by a human eye. Illuminance is measured in footcandles or lux -- one lux is one lumen per square meter.
Try: Lighting Design Lab, an informative source on lighting products, offers a glossary of technical terms, including illuminance.

Photoelectric sensors

A photoelectric sensor is a device used to detect the distance, absence or presence of an object by using a light transmitter. A photoelectric sensor emits invisible infrared or visible red light to detect the presence of an object.
Try: www.electronics-manufacturers.com, an online resource for electronic products, provides information on the working of photoelectric sensors.

Phototransistors

A phototransistor is a semiconductor device that is highly sensitive to light. Phototransistors are used to switch or amplify current and can conduct current in either direction.
Try: PerkinElmer, Inc., a manufacturer of optoelectronic products, describes the features and applications of phototransistors.

Fiber optic cables

A fiber optic cable is a medium of signal transmission that transfers messages modulated on to light waves. It consists of a bundle of glass threads that can transmit light waves.
Try: ARC Electronics, a manufacturer of digital cellular modems, explains the concept of fiber optic cables.

Photocells

A photocell (also called photodetector or photosensor) can sense light or other electromagnetic waves. These devices are predominantly used for automatic switching of external lighting.
Try: Makingthings, a service provider of digital devices, provides an overview of photocell sensors.