Explain the difference between forward biased and reversed biased diodes in terms of current flow ?

In a forward biased diode, the positive terminal of the voltage source is connected to the anode of the diode, and the negative terminal is connected to the cathode. This allows current to flow through the diode, as the voltage applied across the diode is greater than the built-in potential barrier. The diode conducts current in the forward direction, allowing electrons to flow from the n-type material to the p-type material.

In a reverse biased diode, the positive terminal of the voltage source is connected to the cathode of the diode, and the negative terminal is connected to the anode. This creates a high potential barrier at the junction, preventing current from flowing through the diode. The diode does not conduct current in the reverse direction, as the voltage applied across the diode is less than the built-in potential barrier. Only a small leakage current, known as reverse saturation current, flows through the diode in the reverse direction.

Forward Biased Diode

- When a positive voltage is applied to the anode (P-type) and a negative voltage is applied to the cathode (N-type), the diode is said to be forward biased.
- This causes the depletion region to narrow, allowing majority carriers (holes from the P-type and electrons from the N-type) to diffuse across the junction.
- This diffusion creates a current flow from anode to cathode. The forward current increases as the forward bias voltage increases.

Reverse Biased Diode

- When a negative voltage is applied to the anode and a positive voltage is applied to the cathode, the diode is said to be reverse biased.
- This causes the depletion region to widen, effectively blocking the diffusion of majority carriers.
- As a result, the current flow becomes negligible. The reverse current is very small and remains relatively constant regardless of the applied reverse bias voltage.