PRACTICAL # 02To draw the I-V curve of Si diode in forward

biasedBy: Engr.Irshad Raheem Memon

OBJECTIVEObjective of this practical is to learn that how

a diode can be made forward biased and what are the values of voltage across and current through forward biased diode.

Some Concept Regarding Diode & its Forward Bias OperationWhat is Diode? Diode is a two terminal semiconductor

device with an ability to conduct current only in one direction after a certain amount of voltage called barrier potential is applied to it in a proper way.

Diode Forward Bias OperationDiode is said to be forward biased; if positive

terminal of diode is connected with positive of voltage source and negative terminal of diode is connected with negative of voltage source.

Diode Connected in Forward Bias

Forward Bias operation Silicon diode will conduct current at 0.7volt

and germanium diode will conduct current at 0.3volt when forward biased. 0.7volt is also called barrier potential for silicon diode and 0.3volt is barrier potential for germanium diode. Before the value of voltage across diode reaches its barrier potential; there is very small amount of current that is flowing through diode. After the value of voltage across diode reached its barrier potential; there is a rapid change in the value of current through diode.

Detail Operation of Forward Bias with the help of pictureForward Bias Diode showing flow of Majority

Carriers and the Voltage due to barrier potential across the Depletion Region

Its picture will be shown in next slide

Picture Showing F.B Operation

V-I Characteristics of Si & Ge Diode

Coming Towards Objective NowRequired Apparatus:- Few diodes Breadboard Multimeter Connecting wire

ProcedureConnect positive terminal of a diode with

positive of battery and connect negative terminal of a diode with negative of battery and current limiting resistor may also be added in series with diode.

Voltmeter is Connected in parallel with diode and Ammeter is connected in series with diode

Procedure Figure in Multism

OBSERVATIONWhen value of forward voltage across diode

is less than its barrier potential; the value of forward current is very small. As soon as value of forward voltage across diode is reached to its barrier potential; there is rapid increase in forward current.

ANY QUERY?