I-V characteristics of a Zener Diode
AIM: To draw the V-I characteristics of a given Zener diode and to determine the reverse breakdown voltage forward knee voltage and Zener resistance.
APPARATUS: Zener diode, 1KW resistor, DC regulated power supply, voltmeter, milliammeter.
PRINCIPLE: A Zener diode is essentially a heavily doped p-n junction diode.
When the Zener diode is forward biased, the forward current increases with the increase in applied voltage. When it is reverse biased, a small reverse current flows until the breakdown voltage is reached. In the vicinity of breakdown region, the reverse current starts rising rapidly because of avalanche effect. Finally a sharp increase in current occurs when the Zener breakdown voltage (Vz) is reached. In this region, a small voltage change results in a large current change. This voltage limiting characteristics of a Zener diode makes it a good voltage regulator.
PROCEDURE:
FORWARD CHARACTERISTICS:
Connections are made.The voltage is varied gradually and the corresponding current values are noted down.
REVERSE CHARACTERISTICS:
Connections are made.The voltage is varied gradually and the corresponding current values are noted down.
A graph can be plotted with the voltage along X-axis and the current along the Y-axis. During the forward bias, the voltage at which current increases sharply is called forward knee voltage (Vk). In the reverse bias graph, extrapolating straight line portion to the X-axis will yield Zener breakdown voltage. The slope on the linear part of the curve gives Zener resistance,
Rz = DV/DI
RESULTS:
I-V characteristics of a Zener diode are drawn.
The forward knee voltage (Vk) = Volts.
The Zener breakdown voltage (Vz) = Volts.
The Zener resistance (Rz) = Ohms
APPARATUS: Zener diode, 1KW resistor, DC regulated power supply, voltmeter, milliammeter.
PRINCIPLE: A Zener diode is essentially a heavily doped p-n junction diode.
When the Zener diode is forward biased, the forward current increases with the increase in applied voltage. When it is reverse biased, a small reverse current flows until the breakdown voltage is reached. In the vicinity of breakdown region, the reverse current starts rising rapidly because of avalanche effect. Finally a sharp increase in current occurs when the Zener breakdown voltage (Vz) is reached. In this region, a small voltage change results in a large current change. This voltage limiting characteristics of a Zener diode makes it a good voltage regulator.
PROCEDURE:
FORWARD CHARACTERISTICS:
Connections are made.The voltage is varied gradually and the corresponding current values are noted down.
REVERSE CHARACTERISTICS:
Connections are made.The voltage is varied gradually and the corresponding current values are noted down.
A graph can be plotted with the voltage along X-axis and the current along the Y-axis. During the forward bias, the voltage at which current increases sharply is called forward knee voltage (Vk). In the reverse bias graph, extrapolating straight line portion to the X-axis will yield Zener breakdown voltage. The slope on the linear part of the curve gives Zener resistance,
Rz = DV/DI
RESULTS:
I-V characteristics of a Zener diode are drawn.
The forward knee voltage (Vk) = Volts.
The Zener breakdown voltage (Vz) = Volts.
The Zener resistance (Rz) = Ohms
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