PN junction acts as a one way valve for electrons because ___.
A. the circuit in which the diode is used, only attempts to pump electrons in one diode
B. electrons tend to follow the direction of the hole
C. there is a little mechanical switch inside a diode
D. when electrons are pump from P to N, free electrons and holes are force apart leaving no way for electrons to cross the junction
Share your understanding of this question with the correct explanation.