Procedure

• Gather the required equipment:
  • PN junction diode
  • Variable DC power supply
  • Ammeter
  • Voltmeter
  • Connecting wires
  • Resistor (optional, for current limiting)

Fig. 1. Circuit diagram

• Set up the circuit for forward bias:
  • Connect the anode of the diode to the positive terminal of the power supply.
  • Connect the cathode of the diode to one terminal of the ammeter.
  • Connect the other terminal of the ammeter to the negative terminal of the power supply.
  • Connect the voltmeter across the diode to measure the voltage drop.

Procedure

Fig. 2. Transfer curve / V-I characteristics of diode

• Gradually increase the power supply voltage from 0V and record the current through the diode and the voltage across the diode at each step.
• Continue increasing the voltage until a significant increase in current is observed, indicating the forward threshold voltage.
• Turn off the power supply and set up the circuit for reverse bias:
  • Connect the anode of the diode to the negative terminal of the power supply.
  • Connect the cathode of the diode to one terminal of the ammeter.
  • Connect the other terminal of the ammeter to the positive terminal of the power supply.
  • Connect the voltmeter across the diode to measure the voltage drop.
• Gradually increase the reverse bias voltage from 0V and record the current through the diode and the voltage across the diode at each step.
• Continue increasing the voltage until the breakdown voltage is reached, where a significant increase in current is observed.
• Turn off the power supply and disconnect the circuit.
• Plot the IV characteristics of the diode using the recorded data, showing both the forward and reverse bias regions.

This procedure helps in understanding the behavior of a PN junction diode under different biasing conditions, providing practical insights into its IV characteristics.