In which direction does current flow in a diode?

• A. From P-type to N-type
• B. From N-type to P-type
• C. In both directions
• D. Outward only

Answer: (B)

The current in a diode flows from the P-type material to the N-type material when the diode is forward-biased. In a diode, the P-type side contains an abundance of holes (positive charge carriers), while the N-type side contains an abundance of electrons (negative charge carriers). When a voltage is applied in the correct direction, holes from the P-type material move toward the N-type, and electrons from the N-type material move toward the P-type. This flow of charge results in a net current flowing from the P-type to the N-type region.

In reverse bias, the diode does not conduct current; instead, any small leakage current may flow in the opposite direction, but this is not the primary direction of current flow being asked about. Thus, the primary and correct assertion is that during the forward bias condition, current flows from the P-type to the N-type material.