E7D06 — Amateur Extra Class

Question diagram
E7D06 : What is the purpose of Q1 in the circuit shown in Figure E7-2?
A It provides negative feedback to improve regulation
B It provides a constant load for the voltage source
C It controls the current to keep the output voltage constant
D It provides regulation by switching or chopping the input DC voltage
Correct Answer: It controls the current to keep the output voltage constant