In a PN junction, when the applied voltage overcomes the potential barrier, the diode current is large. This is known as A- Depletion, negative bias B- Reverse, reverse bias C- Resistance reverse bias D- Barrier, forward bias. A PN junction A- Has low resistance in forward as well as reverse directions B- Has high resistance in forward as well as reverse directions C- Conducts in forward direction only D- Conducts in reverse direction only. PN junction failure below 5 V is caused primarily by A- Avalanche breakdown B- Zener breakdown C- Either of (A) and (B) above D- None of the above.