Editing Linear regulator (section)

{{Short description|Type of voltage regulator}}
{{Refimprove|date=January 2008}}
[[file:Voltage Regulator connections-en.svg|300px|thumb|Block scheme for voltage regulator in an electronic circuit]]
In [[electronics]], a '''linear regulator''' is a [[voltage regulator]] used to maintain a steady voltage.<ref>{{Cite web |title=Understanding linear regulator and their key performance |url=https://www.renesas.com/document/whp/understanding-linear-regulators-and-their-key-performance-parameters?language=en}}</ref> The resistance of the regulator varies in accordance with both the input voltage and the load, resulting in a constant voltage output. The regulating circuit varies its [[Electrical resistance and conductance|resistance]], continuously adjusting a [[voltage divider]] network to maintain a constant output voltage and continually dissipating the difference between the input and regulated voltages as [[waste heat]]. By contrast, a ''[[switching regulator]]'' uses an active device that switches on and off to maintain an average value of output. Because the regulated voltage of a linear regulator must always be lower than input voltage, efficiency is limited and the input voltage must be high enough to always allow the active device to reduce the voltage by some amount.

Linear regulators may place the regulating device in parallel with the load ([[Shunt (electrical)|shunt]] regulator) or may place the regulating device between the source and the regulated load (a series regulator). Simple linear regulators may only contain as little as a [[Zener diode]] and a series resistor; more complicated regulators include separate stages of voltage reference, error amplifier and power pass element. Because a linear [[voltage regulator]] is a common element of many devices, single-chip regulators [[integrated circuit|ICs]] are very common. Linear regulators may also be made up of assemblies of discrete solid-state or [[vacuum tube]] components.

Despite their name, linear regulators are [[Linear_circuit#Linear_and_nonlinear_components|non-linear circuits]] because they contain non-linear components (such as Zener diodes, as shown below in the [[#Simple_shunt_regulator|simple shunt regulator]]) and because the output voltage is ideally constant (and a circuit with a constant output that does not depend on its input is a non-linear circuit).<ref name="Apte_2016">{{cite book | title = Signals and Systems: Principles and Applications | first = Shaila Dinkar | last = Apte | publisher = Cambridge University Press | year = 2016 | page = 183 | isbn = 978-1-107-14624-2}}</ref>