What is Diode? What happen at a P-N junction?
A diode is a semiconductor two terminal device that allow current to flow in one direction. Diode have polarity, determined by an anode(positive terminal) & cathode (negative terminal) When a diode allows current flow, It is forword biased. When a diode is reverse biased, It acts as an insulator & don't permit current to flow. Formation of P-N junction- In a P-N junction, the P-region has high concentration of holes & very few electrons. Where as the N-region has high concentration of electron & few holes.The electrons from N-region diffuse through the junction into P-region & hole from P-region diffuse into N-region. Depletion region- Due to diffusion, neutrality of both N and P type semiconductor is distributed,a layer of negative charged ions apper near the junction in the P- crystal & a layer of positive ions appear near the junction in N-crystal. This layer is called depletion layer & region in called deplet...