What components are typically found in a three-terminal regulator?

A three-terminal regulator is designed to provide a stable output voltage from a varying input voltage, and it typically includes several crucial components that ensure this function. The correct answer highlights the presence of a voltage reference, which is essential for setting a precise output voltage level. The voltage reference serves as a stable point that the regulator can use to maintain the desired output.

The error amplifier compares the output voltage to the voltage reference. If there is a difference, the error amplifier adjusts the output to bring it back to the target level. This feedback mechanism is key to the regulator’s ability to maintain stability despite variations in input voltage or load conditions.

Sensing resistors are used to monitor the output voltage level, feeding this information back to the error amplifier. This real-time feedback is critical for the regulator's performance, ensuring that any fluctuations are promptly corrected.

Transistors are utilized within the three-terminal regulator to act as a pass element. They allow the regulator to control the amount of current flowing to the output while maintaining the desired voltage.

The combined function of these components—providing a stable reference voltage, amplifying the difference between the output and reference, sensing output voltage, and regulating current flow—enables the three-terminal regulator to function effectively and reliably.