Experiment No.

Object: - TO study PN-junction diode characteristic

Apparatus used: - Model No. ME 539D is used for this experiment.

S.N. Apparatus Type Range Quantity Remark1 Voltmeter mc 0-3 v 1 no. ME 539D2 Voltmeter mc 0-30 v 1 no. Made by

MASS3 Ammeter mc 0-10 M.A. 1 no.4 Ammeter mc 0-100 M.A. 1 no.5 PN-junction diode germanium 1 no.6 Connecting wires PVC 5 Amp.7 potentiometer 1 no.8 Rheostat

Theory: - The diode is a two terminal device. The v-I characteristics of a PN- diode represents a curve between the external voltage applied across it’s terminals and the current that flow through the diode due to this applied voltage.There are two types of characteristics:-

1. forward bias characteristic2. reverse bias characteristic

Forward Bias--

When the positive terminal of the battery is connected to the p-type semiconductor and negative terminal of the battery is connected to the n –type semiconductor .

Forward bias connection with v-I characteristics

Reverse-bias-connection with V-I characteristic

Reverse Bias- When the positive terminal of the battery is connected to the n-type semiconductor and negative terminal of the battery is connected to the p-type semiconductor.

Procedure:-for forward bias characteristic

1. Make the connection as per the ckt. Diagram.2. Apply the variable voltage across the diode with the help of

potentiometer.3. Note the corresponding current from millimeter and voltage from

voltmeter.4. Repeat the procedure again.5. Plot the graph between forward voltage and current.

For reverse biased

1. Now connect the ckt. As per the diagram.2. Apply the variable voltage across the diode with the help of

potentiometer.3. Note down the corresponding current from micro ampere meter and

voltage from voltmeter.4. Repeat the process again.5. Plot the graph between reverse voltage and current.

Observation:-

S.N. Forward biased Reverse biasedvoltage Current Voltage current

1234

Result: - discuss the nature of the curves obtain for forward and reverse mode.

Precautions:-1. All connections should be tight.2. All steps should be followed carefully.3. Reading should be taken carefully.4. Do not touch the live terminal.5. Never increases reverse biased voltage up to the breakdown voltage.