Investigating the Characteristics of Semiconductor PN Junction Diode
Objective: The objective of this laboratory activity is to understand the basic characteristics of a semiconductor PN junction diode.
Materials:
- Semiconductor PN junction diode
- Breadboard
- DC power supply
- Resistors (100 ohm, 1 kohm)
- LED bulbs (red, green, and blue)
- Connecting wires
Procedure:
- Connect the semiconductor PN junction diode on the breadboard.
- Connect the positive terminal of the DC power supply to the anode (positive terminal) of the PN junction diode and the negative terminal to the cathode (negative terminal) of the diode.
- Insert a 100 ohm resistor in series with the anode of the diode and connect a red LED bulb to the resistor and the cathode of the diode.
- Observe the brightness of the LED bulb and record your observation.
- Reverse the polarity of the DC power supply by connecting the negative terminal to the anode of the diode and the positive terminal to the cathode.
- Insert a 100 ohm resistor in series with the anode of the diode and connect a green LED bulb to the resistor and the cathode of the diode.
- Observe the brightness of the LED bulb and record your observation.
- Calculate the forward bias voltage and the reverse bias voltage of the diode.
- Replace the 100 ohm resistor with a 1 kohm resistor and repeat steps 3-4.
- Replace the 100 ohm resistor with a 1 kohm resistor and repeat steps 6-7.
- Observe the differences in the brightness of the LED bulbs for the two different resistances.
- Discuss the results and explain the behavior of the diode under forward and reverse bias conditions.
This is how the circuit looks like:
