What does the term "forward-biased" mean in the context of a transistor?

In the context of a transistor, the term "forward-biased" refers to a condition in which a voltage is applied to the transistor's junction that supports the flow of current. This means that the positive voltage is applied to the base terminal of a bipolar junction transistor (BJT) or to the gate of a field-effect transistor (FET), allowing electrons to flow easily through the device.

When a junction is in a forward-biased state, it reduces the barrier potential that normally exists in junctions, allowing charge carriers to move across the junction. In the case of a BJT, for example, when the base-emitter junction is forward-biased, it allows current to flow from the emitter to the collector, leading to amplification or switching functionality in circuits.

This concept is fundamental to the operation of bipolar transistors and other semiconductor devices, as forward bias is essential for enabling their active operation. The other options do not accurately describe the behavior or implications of forward bias in a transistor: they either describe conditions that block current flow or do not relate to the supportive role of voltage for current movement in the device.