In this article, we learn about Biasing of PN Junction in detail – like how to bias a PN junction Diode (Forward & Reverse bias methods), the behavior of PN junction during forward & reverse bias, how to plot the Voltage-Current characteristics, and many other essential concepts regarding a PN junction diode. So let’s begin.

Biasing of PN Junction:

Biasing means applying external voltages to the device, biasing of a PN Junction diode is of two types: Forward Biasing and other one is Reverse Biasing.

Forward Biasing of Diode: In Forward biasing of PN Junction the positive terminal of the battery is connected with the P-type Material and Negative terminal of the battery is connected with the N-type material, hence this configuration is called as Forward Bias Configuration of Diode. In this configuration PN Junction Diode allows the current to flow in uni-direction.

Reverse Biasing of Diode: In Reverse biasing of PN Junction the Negative Terminal of the Battery is connected to the P-type Material and Positive terminal of the Battery is connected to the N-type Material, hence this configuration is called as Reverse Bias configuration of Diode. In this configuration, PN Junction diode does not allow the flow of current.

Biasing of PN Junction

Forward Bias V-I Characteristics of PN Junction Diode:

When a forward-bias voltage is applied across a PN Junction, there is current. This current is called as the forward current.

When the forward bias voltage is increased to a value where the voltage across the diode reaches approximately 0.7 V (barrier potential), the forward current begins to increase rapidly, as shown in Figure given below.

Barrier Potential means property of the material to oppose voltages

As you continue to increase the forward-bias voltage, the current continues to increase very rapidly, but the voltage across the diode is constant up to 0.7v for silicon and 0.3v for germanium.PN junction diode on forward bias

Reverse Bias V-I Characteristics of PN Junction

When a reverse bias is applied across a PN junction, there is an extremely small reverse current (IR) through the PN junction due to minority carriers.

Once the applied voltage is increased to a value where the reverse voltage across the diode reaches the breakdown value of the diode which is (VBR), the reverse current begins to increase rapidly.

As you further increase the bias voltage, the voltage across the diode increases above Breakdown, and diode become damaged, thus it’s not a normal mode of operation for most PN junction diodes.

PN junction diode on Reverse bias

For more Information of PN JUNCTION DIODES:

  1. Read: What is PN JUNCTION DIODE
  2. Read: Forward Bias of PN JUNCTION DIODE
  3. Read: Reverse Bias of PN JUNCTION DIODE
  4. Read: Applications of PN JUNCTION DIODE
  5. Read: Types of PN JUNCTION DIODE
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