Question

Reverse saturation current of silicon diode formula

Answer 1

Diodes

A diode is formed by a PN-junction with the p side called anode and the n side called cathode. Due to the fact that there exist few freely movable charge carriers in the depletion region around the PN-junction, the conductivity is very poor. However, when external voltage is applied to the two ends of the material, the conductivity may change, depending one the polarity of the applied voltage.



Forward bias (positive to P-type, negative to N-type)

The positive voltage applied to the P-type will pull electrons in N-type and repel holes in P-type so that both carriers are moving towards the PN-junction. As the depletion region becomes thinner, the conductivity increases due to the drift current through the PN-junction from the P side to the N side, formed by the majority charge carriers (both electrons and holes) driven by the applied voltage. The conductivity increases as the applied voltage becomes higher.