When the depletion region meets an equilibrium, this produces what?

When the depletion region meets an equilibrium, this produces what?

• A. A potential barrier zone that prevents electrons from moving into the anode from the cathode
• B. A region of increased current flow
• C. A superconductive path forms
• D. A reduction in depletion width

Answer: (A)

When a PN junction is in equilibrium, diffusion of carriers creates a region depleted of mobile charges, establishing an internal electric field and a built-in potential across the junction. This built-in potential acts as a barrier, so there is no net current flow. In other words, it blocks further movement of electrons from the n-type side (cathode) toward the p-type side (anode) unless external bias is applied. Forward bias lowers this barrier and allows current; reverse bias raises it.

When a PN junction is in equilibrium, diffusion of carriers creates a region depleted of mobile charges, establishing an internal electric field and a built-in potential across the junction. This built-in potential acts as a barrier, so there is no net current flow. In other words, it blocks further movement of electrons from the n-type side (cathode) toward the p-type side (anode) unless external bias is applied. Forward bias lowers this barrier and allows current; reverse bias raises it.