☑ How Does A Voltage Dependent Resistor Work

They are often used to protect circuits against excessive transient voltages. This article gives an overview of what is ldr light dependent resistor circuit and its working.

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For instance when the ldr is in darkness then it can be used to turn on a light or to turn off a light when it is in the light.

How does a voltage dependent resistor work. A varistor is an electronic component with an electrical resistance that varies with the applied voltage. To overcome this problem we can use the light dependent resistor circuit for controlling the loads based on the intensity of light. When light falls upon it then the resistance changes.

The impedance is high under nominal load conditions but will sharply decrease to a low value when a voltage threshold the breakdown voltage is exceeded. A photoresistor or light dependent resistor is a component that is sensitive to light. But unlike a variable resistor whose resistance value can be manually varied between its minimum and maximum values the varistor changes its resistance value automatically with the change in voltage across it making it a voltage dependant non linear resistor or vdr for short.

Working principle of ldr. An ldr or a photoresistor is a device that is made up of high resistance semiconductor material. A voltage dependent resistor has a nonlinear varying resistance dependent on the voltage applied.

This resistor works on the principle of photo conductivity. Values of the resistance of the ldr may change over many orders of magnitude the value of the resistance falling as the level of light increases. A typical light dependent resistor has a resistance in the darkness of 1mohm and in the brightness a resistance of a couple of kohm.

In contrast to a diode however it has the same characteristic for both directions of traversing current. Also known as a voltage dependent resistor vdr it has a nonlinear non ohmic currentvoltage characteristic that is similar to that of a diode.