Light Dependent Resistor Graph

A photoresistor can be applied in light sensitive detector circuits. As the light level changes the resistance of the ldr changes over a huge range.

National 5 Assignment Ldr Distance Guide Sheet A

Non Ohmic Devices Filament Lamp Led Ldr Diode V I

Light Dependent Resistor Ldr Lednique

It has the symbol.

Light dependent resistor graph. Typical ldr resistance vs light intensity graph. Hence it can be considered a sensor or light sensor. The resistance of a light dependent resistor is large in the dark.

This is difficult to plot onto normal graph paper so logarithmic graphs are used. Photo resistors also known as light dependent resistors ldr are light sensitive devices most often used to indicate the presence or absence of light or to measure the light intensity. In the dark their resistance is very high sometimes up to 1mw but when the ldr sensor is exposed to light.

In other words it exhibits photoconductivity. The resistance of a thermistor depends on its temperature. The light dependent resistor ldr in a light dependent resistor the resistance decreases as the light intensity brightness of light increases.

Variation in resistance with changing light intensity. An ldr is a type of variable resistor which changes its resistance according to the intensity of the light falling on its surface. The higher the temperature the lower the resistance.

A photoresistor or light dependent resistor ldr or photo conductive cell is a light controlled variable resistor. If the resistance is 3kw the light level is 20 lux. At low light levels or in the dark the resistance of an ldr is high and little current flows through it.

The resistance of a photoresistor decreases with increasing incident light intensity. In bright light the resistance of an ldr is low and more current flows through it. Their resistance decreases as the light intensity increases.

Hence they are light sensitive devices. The resistance gets less if light shines on it. They are made up of semiconductor materials having high resistance.

If the resistance is 20kw the light level is about 042 lux. Explain the correlation between thermistors and resistance. They are also called as photo conductors photo conductive cells or simply photocells.

What is an ldrlight dependent resistor or photoresistor. Graph between intensity of light and the resistance of ldr. The symbol of the resistor and arrows as described above is used by the light dependent resistors in majority of their applications.

This is evident in the case when circuit diagrams are drawn. Light dependent resistor ldr ldrs light dependent resistors are used to detect light levels for example in automatic security lights. The brighter the light the lower the resistance.

But there are few cases where the symbol used by the light dependent resistors depicts the resistor encased within a circle. The most common type of ldr has a resistance that falls with an increase in the light intensity falling upon the device as shown in the image above. A light dependent resistor ldr or a photo resistor is a device whose resistivity is a function of the incident electromagnetic radiation.