| Aim | To draw the characteristics curve of a Zener diode and to determine its reverse breakdown voltage. |
| Apparatus Required | Zener diode DC power supply Rheostat or potentiometer Ammeter Voltmeter Connecting wires |
| Theory | A Zener diode is a type of diode that is designed to operate in the reverse breakdown region, also known as the Zener region. When a reverse bias voltage is applied to a Zener diode, the electric field across the depletion region increases, causing the diode to conduct current in the reverse direction. The voltage at which the Zener diode starts to conduct is known as the reverse breakdown voltage or the Zener voltage. |
| Procedure | Connect the Zener diode to the DC power supply, rheostat or potentiometer, ammeter, and voltmeter using connecting wires. Set the rheostat or potentiometer to its maximum value. Connect the ammeter in series with the Zener diode and the voltmeter in parallel. Gradually decrease the reverse bias voltage by adjusting the rheostat or potentiometer and record the corresponding values of current and voltage. Plot the I-V characteristics curve for the Zener diode. Determine the reverse breakdown voltage or the Zener voltage from the curve. |
| Observation and Result | Observation: In reverse bias, the current initially remains low but increases rapidly at a certain voltage known as the reverse breakdown voltage or the Zener voltage. The I-V characteristics curve for a Zener diode is a straight line in the breakdown region. The reverse breakdown voltage or the Zener voltage can be determined from the curve. Result: The I-V characteristics curve for a Zener diode has been successfully plotted. The curve shows the relationship between current and voltage for the Zener diode in reverse bias. The reverse breakdown voltage or the Zener voltage for the Zener diode has been determined from the curve. |