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What are photoresistors used for?
Photoresistors, also known as LDR (light-dependent resistors), are components made of semiconductors. A photoresistor is sensitive to light. Its resistance decreases when lighting increases (Figure 1.15). Photoresistors have multiple uses, for example, automatic door opening.
Is Photoresistor a diode?
Photodiodes use the optical characteristics of semiconductor materials to realize the switching function of diodes. Although sometimes the same material is used for both materials such as silicon and gallium arsenide, the material range of the photoresistor is wider than that of the photodiode.
How are Photoresistors used in a security system?
Photoresistors or LDRs are also used in laser-based security systems to detect the change in the light intensity when a person/object passes through the laser beam. They are also used in some dynamic compressors together with a small incandescent or neon lamp, or light-emitting diode to control gain reduction.
What is the sensitivity of a photoresistor to light?
The sensitivity of the photoresistor to light (the spectral characteristics) is very close to the human eye’s response to visible light (0.4~0.76) μm. As long as the human eye can sense the light, it will cause its resistance to change.
How are extrinsic Photoresistors used in the real world?
Extrinsic photoresistors are used for detecting the longer wavelength and lower frequency light. Higher the light intensity, larger the resistance drop of the photoresistor. The sensitivity of photoresistors varies with the wavelength of the light applied.
How to write analog value on photoresistor monitor?
In the ” void setup ” we initialize the serial monitor : Then, we read the analog value coming from photoresistor and we define it as ” value ” : And we write the value on the serial monitor : Second pin –> A0 ( a resistance is connected to the GND and to the photoresistor second pin ).