When a diode is reverse-biased, it does not completely stop current flow; instead, a small reverse leakage current, known as Is, occurs. The diode's behavior can be understood through the diode equation and its I-V characteristic, which illustrates how electrons face a potential barrier. In reverse bias, electrons from the heated cathode flow towards the plate when the cathode is negative, but this flow halts when the cathode is positive. The discussion clarifies that the mention of a common diode rectifier refers to vacuum tubes, not semiconductor diodes, to avoid confusion. Understanding these principles helps explain why current does not reach zero in reverse bias conditions.
