What are CdS Cells?
What are CdS Cells?
A CDS photocell (or Light Dependant Resistor / LDR) is a resistor where the resistance changes based on the amount of light.These make great basic light sensors as they are extremely easy to use. As the amount of light increases the resistance of the sensor decreases and vice versa.
Photocells are sensors that allow you to detect light. They are small, inexpensive, low-power, easy to use and don't wear out.For that reason they often appear in toys, gadgets and appliances. They are often referred to as CdS cells (they are made ofCadmium-Sulfide), light-dependent resistors (LDR), and photoresistors.
Photocells are basically a resistor that changes its resistive value (in ohms Ω) depending on how much light is shining onto the squiggly face. They are very low cost, easy to get in many sizes and specifications, but are very innacurate. Each photocell sensor will act a little differently than the other, even if they are from the same batch. The variations can be really large, 50% or higher! For this reason, they shouldn't be used to try to determine precise light levels in lux or millicandela. Instead, you can expect to only be able to determine basic light changes.
For most light-sentsitive applications like "is it light or dark out", "is there something in front of the sensor (that would block light)", "is there something interrupting a laser beam" (break-beam sensors), or "which of multiple sensors has the most light hitting it", photocells can be a good choice!
Some Basic StatsThese stats are for the photocell in the Adafruit shop which is very much like the PDV-P8001 . Nearly all photocells will have slightly different specifications, although they all pretty much work the same. If there's a datasheet, you'll want to refer to it.
Sensitivity range: CdS cells respond to light between 400nm (violet) and 600nm (orange) wavelengths, peaking at about 520nm (green).
Latest News
Contact Us
Name: Miss zhao
Tel: +86-13333651153
E-mail: [email protected]
Skype: helenlystone
Add: Shenzhen,China
Link
Skype Chat
Mail inquiry