Extra element theorem

The Extra Element Theorem (EET) is an analytic technique developed by R. D. Middlebrook for simplifying the process of deriving driving point and transfer functions for linear electronic circuits.^[1] Much like Thévenin's theorem, the extra element theorem breaks down one complicated problem into several simpler ones.

Driving point and transfer functions can generally be found using Kirchhoff's circuit laws. However, several complicated equations may result that offer little insight into the circuit's behavior. Using the extra element theorem, a circuit element (such as a resistor) can be removed from a circuit, and the desired driving point or transfer function is found. By removing the element that most complicate the circuit (such as an element that creates feedback), the desired function can be easier to obtain. Next, two correctional factors must be found and combined with the previously derived function to find the exact expression.

The general form of the extra element theorem is called the N-extra element theorem and allows multiple circuit elements to be removed at once.^[2]

^ Vorpérian, Vatché (2002). Fast analytical techniques for electrical and electronic circuits. Cambridge UK/NY: Cambridge University Press. pp. 61–106. ISBN 978-0-521-62442-8.
^ Vorpérian, Vatché (2002-05-23). Fast Analytical Techniques for Electrical and Electronic Circuits. pp. 137–139. ISBN 978-0-521-62442-8.

[Vorpérian-1] Vorpérian, Vatché (2002). Fast analytical techniques for electrical and electronic circuits. Cambridge UK/NY: Cambridge University Press. pp. 61–106. ISBN 978-0-521-62442-8.

[Vorpérian2-2] Vorpérian, Vatché (2002-05-23). Fast Analytical Techniques for Electrical and Electronic Circuits. pp. 137–139. ISBN 978-0-521-62442-8.

[1]

[2]