What is reverse bias in a diode?

Reverse bias in a diode refers to the condition where the voltage is applied in such a way that it prevents current from flowing through the device. In this state, the diode is effectively "off," acting as an insulator. The applied voltage causes the p-n junction to widen the depletion region, which increases the barrier for charge carriers, thereby inhibiting the flow of current. This is crucial in circuit design, especially in applications where diodes are used for rectification or in circuits that require protection against reverse current.

Understanding reverse bias helps clarify how diodes function in different applications. This is particularly important in ensuring that diodes reliably prevent unwanted current in situations where it could damage other components in a circuit.