Advantages of Light sensor | Disadvantages of Light sensor
This page covers advantages and disadvantages of Light sensor. It mentions Light sensor advantages and Light sensor disadvantages.
Definition: The sensor device used to sense light is known as light sensor. It converts light input into corresponding electrical output. It is used in automatic street light system, automatic brightness control in mobile, security devices in home and office, to measure light seen by the camera etc.
There are various types of light sensors which include photo conductive cell,
photo voltaic cell and photo junction devices (photo diode, photo transistor).
Most commonly used light sensors are based on photo resistors which control flow of current
using sensed light energy. These are known as Light Dependent Resistors (LDRs).
Refer Light sensor basics and types >> for more information.
The advantages and disadvantages of light sensors depend on the construction process viz. photoresistor, photodiode or phototransistor.
Advantages of Light sensor
Following are the advantages of Light sensor :
➨It is easy to integrate with lighting system such as automatic lighting system.
➨It is used for energy consumption or energy management by automatic control of brightness level in mobile phones and auto ON/OFF of street lights based on ambient light intensity.
➨LDR (i.e. photoresistor) based light sensors are available in different shapes and sizes.
➨Light sensors need small voltage and power for its operation.
➨Photoresistors are lower in cost, bi-directional and offer moderate response time.
➨Photodiodes offer quick response time, lower in cost and provide digital output.
➨Phototransistors are very fast and provide immediate output compare to photoresistors.
➨Phototransistors generate high current compare to photodiodes.
Disadvantages of Light sensor
Following are the disadvantages of Light sensor :
➨LDRs are highly inaccurate with high response time (about 10s or 100s of milliseconds).
➨Resistance varies continuosly (analog) in photoresistor and are rugged in nature.
➨Photodiodes are temperature sensitive and are uni-directional unlike photoresistors.
➨Phototransistors can not withstand voltages above 1000 volts.
➨Phototransistors are vulnerable to surges, spikes and EM energy.
Also refer advantages and disadvantages of Photoelectric sensor >>.
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