What is the name of the component labeled Q1 as shown in section "D" of the regulated DC power supply illustrated? Illustration EL-0085

Correct Answer: Option B — NPN bipolar junction transistor

Component Q1 functions as the series pass element in a linear voltage regulator circuit. Classified under semiconductor standards as an NPN bipolar junction transistor, it varies its collector-emitter resistance to maintain a constant output voltage despite load fluctuations.