To use a transistor as a simple solid-state relay, what conditions must occur?
A) The emitter-base junction must be reverse biased, and the collector-base junction must be forward biased.
B) The emitter-base junction must be forward biased, and the collector-base junction must be reverse biased.
C) The emitter-base junction and the collector-base junction both must be forward biased.
D) The emitter-base junction and the collector-base junction both must be reverse biased.

Question

Quizplus · Accepted Answer

When the emitter-base junction is forward biased and the collector-base junction is reverse biased, the transistor is in cutoff mode (i.e., it doesn't conduct). When the emitter-base junction is reverse biased and the collector-base junction is forward biased, the transistor is in saturation mode (i.e., it conducts fully). By controlling the biasing of these two junctions, we can use a transistor as a solid-state relay. In this case, we want the transistor to act like a switch, so we want it to be either fully conducting (on) or fully cutoff (off). Therefore, we need to bias the emitter-base junction forward and the collector-base junction reverse to achieve this result.

To Use a Transistor as a Simple Solid-State Relay, What