What type of voltage regulator contains a voltage reference, error amplifier, sensing resistors and transistors, and a pass element in one package?

A three-terminal regulator is a complete integrated circuit (IC) voltage regulator packaged into a single component with just three connections: input, output, and ground. Inside this compact package, it contains all the necessary circuitry for regulation, including a voltage reference, error amplifier, sensing components, and a series pass transistor. While an op-amp regulator or a switching regulator might use some of these same functional blocks, they typically require external components or describe a broader circuit topology rather than a single packaged element. A simple Zener regulator only consists of a Zener diode and a resistor, lacking the sophisticated error amplifiers and sensing transistors found in an IC.