20mm LDR Sensor
LDR 20mm – Light Dependent Resistor Sensor is a resistor whose resistance decreases with increasing instance light intensity; in other words, it exhibits
A photo-resistor is made of a high resistance semiconductor. If light falling on the device is of high enough frequency, photons absorb by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electron (and its hole partner) conduct electricity, thus lowering resistance. LDR(Light Dependent Resistor Sensor) also known as photoresistor is a resistor whose resistance varies with the amount of light falling on it. This is a small size LDR with a size of 4mm.
To use, connect one side of the photocell (either one, it’s symmetric) to power (for example 5V) and the other side to your microcontroller’s analog input pin. Then connect a 10K pull-down resistor from that analog pin to ground. The voltage on the pin will be 2.5V or higher when it’s light out and near the ground when its dark. This sensor can be use for making a light sensor, color sensor, object sensor, line sensor, etc.
- Small open frame package.
- Epoxy coated.
- Moisture resistant.
- Spectral response is similar to the human eye.
- Camera Exposure Control.
- Auto Slide Focus – dual cell.
- Photocopy Machines – thickness of toner.
- Colorimetric Test Equipment.
- Electronic Scales – twin cell.
- Automatic Gain Control modulated light source.
- Automated Rear View Mirror.
- Automatic Headlight Dimmer.
- Night Light Control.
- Oil Burner Flame Out.
- Street Light Control.
- Absence / Presence (beam breaker).
- Site Sensor.