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In the case of a frequency dependent applied voltage or current, the impedance may be dependent upon frequency and exhibit a phase dependent upon frequency, as normally expressed using an impedance represented by a complex number. | In the case of a frequency dependent applied voltage or current, the impedance may be dependent upon frequency and exhibit a phase dependent upon frequency, as normally expressed using an impedance represented by a complex number. | ||
==Example== | |||
{{Image|Current follower.PNG|right|300px|Bipolar current follower.}} | |||
==References== | ==References== | ||
Revision as of 19:57, 21 May 2011
In the theory of electrical circuits, Norton's theorem allows the replacement of a two-terminal portion of a linear circuit by a simplified circuit consisting of a current source, called the Norton voltage source, in parallel with an impedance, called the Norton impedance. Norton's theorem is the dual of Thévenin's theorem, which replaces a two-terminal portion of a linear circuit by a simplified circuit consisting of a voltage source in series with an impedance.[1]
Finding the Norton components
To determine the Norton current, short circuit the two terminals and measure or calculate the short-circuit current between the terminals.
To determine the Norton impedance, set all independent sources between the two terminals to zero (leave the dependent sources active), and determine the impedance seen looking into the two terminals. For example, apply a known voltage across the port terminals and measure the current drawn, or apply a known current and determine the voltage developed. The Norton impedance is then the ratio of the voltage across the terminals to the current passing through the terminals.
In the case of a frequency dependent applied voltage or current, the impedance may be dependent upon frequency and exhibit a phase dependent upon frequency, as normally expressed using an impedance represented by a complex number.
Example
References
- ↑ Adel S Sedra and Kenneth C Smith (1998). “Appendix E: Some useful network theorems”, Microelectronic circuits, 4rth ed. Oxford University Press, pp. E-1 ff. ISBN 0-19-511690-9.