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Sealed Metal Photoreistor

A photoresistor (also known as a light-dependent resistor, LDR, or photo-conductive cell) is a passive component that decreases resistance with respect to receiving luminosity (light) on the component's sensitive surface. The resistance of a photoresistor decreases with increase in incident light intensity; in other words, it exhibits photoconductivity. 

A photoresistor can be applied in light-sensitive detector circuits and light-activated and dark-activated switching circuits acting as a resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megaohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms. If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance. The resistance range and sensitivity of a photoresistor can substantially differ among dissimilar devices. Moreover, unique photoresistors may react substantially differently to photons within certain wavelength bands.

Sicube,leading manufacturer of Industrial Electronics components and products in China.


Hermetically sealed metal cap photoresistor are a special photoresistor set in an airtight environment with a special metal and glass window. The closed environment is filled with nitrogen, which completely isolates the photoresistor from the outside world, thus effectively extending its life cycle. It is broadly applied in high/low temperature, high humidity, acid, alkali and ultraviolet environments.

SICUBE has the ability to make all kinds of metal cap photoresitor(LDRs).7mm metal photoresistor is the most popular one in the market.

Quick Spec

0.25 WATT

Ambient temperatures: -50 to 150°C

Spectral peak: 540mm

Models: 5mm ,7mm,11mm series

Illuminance resistance at 10 lux: 10kΩ

Dark resistance after 10s: >1MΩ