What is a photocell

A Photo Cell , LDR, or Light Dependant Resistor is used to detect light. Meaning, pronunciation, translations and examples. These sensors improve the security and safety of your home, automatically turning on lights when it gets dark or they detect motion. CdS cells, photoresistors, LDR (light dependent resistor).

For that reason they often appear in toys, gadgets and appliances.

Photocells are sensors that allow you to detect light.

Inlike infrared sensors that are good for line followers or detecting the presense of an object, photocells are good when you just want to detect light.

All these things are examples of photoelectric cells (sometimes called photocells ) —electronic devices that generate electricity when light falls on them. They are are often referred to a . What are they and how do they work? A photoresistor can be applied in light-sensitive detector circuits, and light-activated and dark-activated switching circuits. Because of this effect, they are also known as photoresistorsors or light dependent resistors (LDRs). English dictionary definition of photocell.

They produce DC - direct current - electricity. This is electricity in which the current moves in the same . A major application of photocells is in automatic lighting devices such as dusk-to-dawn lights. Our photocells come in various designs and different attachments for any application.

Used for photographic light meters, automatic on-at-dusk street lights and other light-sensitive applications, a photocell varies its resistance between its two terminals based on the amount of photons (light) it receives. Also called a photodetector, photoresistor and light dependent . One of the most common types of photocell is a. Many embedded devices need to detect light levels. The photocell seen below can cost under $and is available from Adafruit or Sparkfun. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. The way this works is that as the resistance of the photocell decreases, the total resistance of the photocell and the pulldown resistor decreases from over 600KΩ to 10KΩ.

That means that the current flowing through both resistors increases which in turn causes the voltage across the fixed 10KΩ resistor to . When its dark, the sensor looks like an large resistor up to 10MΩ, as the light level increases, the resistance goes down. This graph indicates approximately the resistance of the sensor at different light levels.