Voltage Regulator
The linear IC voltage regulator is a device used to hold the output voltage from a dc power supply relatively constant over a wide range of line and load variations. Most commonly used IC voltage regulators are three-terminal devices.
There are four types of IC voltage regulators: fixed positive, fixed negative, adjustable, and dual tracking. The fixed-positive and fixed-negative IC voltage regulators are designed to provide specific output voltages. The adjustable regulator can be adjusted to provide any dc output voltage within two specified limits. The dual-tracking regulator provides equal positive and negative output voltages.
The regulator input-voltage polarity must match the device’s rated output polarity regardless of the type of regulator used.
IC voltage regulators are series regulators, that is, they contain internal pass transistors and transistor control components. The internal circuitry of an IC voltage regulator is similar to that of the series feedback regulator.