Active Member
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[China]
Address: NO.27,Jinlanling Street,Taigongling Village Dongguan 523829,Guangdong,China
Contact name:Eric
Aolittel Technology Co.,Ltd |
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Dia 5mm Metal Encapsulation LDR Photoresistor Light Sensor With
Dark Resistance 0.2-20 MOhm
Specification
unit:mm
| Item | Type | Max.Voltage (VDC) | Power Dissipation (mw) | Ambient Temperature (℃) | Spectral Response Peak(nm) | Light Resistance (10Lux) KΩ | Dark Resistance MΩ | γ | Response Time (ms) | Illuminance | |
| Increase | Decrease | ||||||||||
φ6.5 | GM5510 | 100 | 100 | -30~+70 | 550 | 5-10 | 0.2 | 0.6 | 30 | 30 | 2 |
| GM5515 | 100 | 100 | -30~+70 | 550 | 10-20 | 1 | 0.7 | 30 | 30 | 3 | |
| GM5525 | 100 | 100 | -30~+70 | 550 | 30-50 | 10 | 0.75 | 30 | 30 | 4 | |
| GM5558 | 100 | 100 | -30~+70 | 550 | 50-100 | 20 | 0.85 | 30 | 30 | 4 | |
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Main Characteristic Curve
How an LDR works
It is relatively easy to understand the basics of how an LDR works
without delving into complicated explanations. It is first
necessary to understand that an electrical current consists of the
movement of electrons within a material. Good conductors have a
large number of free electrons that can drift in a given direction
under the action of a potential difference. Insulators with a high
resistance have very few free electrons, and therefore it is hard
to make the them move and hence a current to flow.
An LDR or photoresistor is made any semiconductor material with a
high resistance. It has a high resistance because there are very
few electrons that are free and able to move - the vast majority of
the electrons are locked into the crystal lattice and unable to
move. Therefore in this state there is a high LDR resistance.
As light falls on the semiconductor, the light photons are absorbed
by the semiconductor lattice and some of their energy is
transferred to the electrons. This gives some of them sufficient
energy to break free from the crystal lattice so that they can then
conduct electricity. This results in a lowering of the resistance
of the semiconductor and hence the overall LDR resistance.
The process is progressive, and as more light shines on the LDR
semiconductor, so more electrons are released to conduct
electricity and the resistance falls further.
Application
Camera automatic photometry
Photoelectric control
Indoor ray control
Annunciator
Industrial control
Light control switch
Light control lamp
Electronic toy
Description
LDR is a small device used to detect variation in light intensity.
It is a kind of variable resistor and the resistance depends on the
intensity of light falling on it.
In total dark, its resistance is as high as 10 Mega Ohms which
reduces to a few Ohms in bright light.
LDR is called as CdS cells because its semiconductor is Cadmium
Sulphide.
Its light sensitive area is doped with impurities like Silver,
Antimony or Indium.
When the light fall on the semiconductor material, flow of
electron- hole pairs occur and electrical conductivity takes place.
In structure, the LDR has a thin Zig-Zag shaped semiconductor line
enclosed in a transparent case.
LDR can handle very high current and even AC passes through it
without harming the device.
Two leads are arising from the two ends of the semiconductor.
LDR is available in sizes 3mm, 5mm,7mm, 10mm,11mm,12mm, 20mm,25mm
etc
