Optocoupler

 Optocoupler :

            An optocoupler is a device that uses a short optical transmission path to transfer a signal  between elements of a circuit, typically transmitter and receiver which are electrically isolated.

            It is basically used as isolator circuit.

Fig. Circuit Symbol of optocoupler

Construction

            Basically optocoupler is a pair of LED and phototransistor enclosed in a single package.

           

            Here LED and phototransistor are isolated so that light may travel across a barrier but electrical current may not.

Working Principle

Specifications and Parameters :

            Device operating temperature.

            Emitter diode characteristics like, forward input current, LED power dissipation, reverse input voltage, reverse leakage current.

            For detector, the maximum collector current, collector-emitter breakdown voltage and power dissipation.

            Turn ON time, turn OFF time.


           

Characteristics for Optocoupler:


   

            Keep V2 constant and vary input voltage V1 in steps.

            Measure the input and output currents and plot the graph to study input-output characteristic for optocoupler.

            Applications

            Optocouplers are mainly used to cut down the ground loops, block voltage spikes and provide electrical isolation.

            They are used to isolate low current control or signal circuitry from transient generated by power supply or current controlled circuits.

            In digital interface of circuits with analog circuits, optocoupler are used to prevent malfunctioning of digital circuits.

            In digital interface of circuits with analog circuits, optocoupler are used to prevent malfunctioning of digital circuits.

For more details visit my You Tube Channel "EasyElectronics"

YouTube link for optocoupler:- https://youtu.be/TdNCiMo4US0

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