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| LDR photoresistor, Working, Types , Application |
LDR photoresistor, Working, Types , Application
The LDR photoresistor is considered one of the most important pieces of electronic components that is widely used in many electronic projects and circuits. In this educational lesson, we will learn about the importance and role of the photoresistor in electrical circuits. What is the definition and components of the LDR photoresistor? What is the symbol of LDR ? What are the most important uses of photoresist in electrical electronic circuits?
Definition of LDR resistor:
photoresistor (also known as a photocell, or light-dependent resistor, LDR, or photo-conductive cell) is a passive component that decreases resistance in light .
LDR It is an electrical resistance that depends primarily on the rays and brightness of light. The greater the rays of light or the sun, the greater its value in resisting electrical current, and vice versa. It is widely used in public lighting circuits, and many other electrical circuits.
LDR resistor symbol:
The photoresistor has a special symbol or symbols that are used in practical diagrams of electronic circuits. Its symbol is distinguished by the presence of two arrows with the symbol for normal electrical resistance. The picture below shows the symbol for the photoresistor (LDR):
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| LDR resistor symbol structure |
LDR photoresistor components :
The photoresistor is made with semiconductor materials, just like the diode and transistor, which we previously talked about in detail. You can read about them below.
Explaining the diode component and how it works in electronic circuits.
Explain the transistor component in detail and explain its components.
The photocell contains two ends to connect it to circuits with other electronic elements. It is of the non-polarized type, meaning it can be connected in any way and is not available on the positive or negative ends. It is often in the form of a circle with wavy lines inside it, as in the following image:
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| LDR resistor components |
How to measure the value of the LDR photoresistor:
To measure LDR photoresistor we use a Multimeter device ( explain Multimeter using ) .
This is done by placing the indicator of the Multimeter device on the unit Ohm. After that, we take the probes of the device and place them on both ends of the LDR, To find out the maximum value of the LDR resistor, we measure it in the dark.
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| Test LDR resistor |
How to know if the photoresistor is damaged or not:
To find out if the photoresistor is damaged or not, measure it while the light is on. If its value is very small, then it is in good condition and ready for use. If it is large while the light is on, it is damaged and must be replaced.
The most important uses of photoresistor LDR:
Photoresistor has countless uses, some of which are:
Photoresistors are widely used in public lighting systems, due to their ease of use and installation.
Used in light sensors.
Used in electronic circuits to control lamps.