Search results
Results From The WOW.Com Content Network
In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. [1]Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. [2]
Parasitic impedance. Parasitic elements of a typical electronic component package. In electrical networks, a parasitic impedance is a circuit element (resistance, inductance or capacitance) which is not desirable in a electrical component for its intended purpose. For instance, a resistor is designed to possess resistance, but will also possess ...
An equivalent impedance is an equivalent circuit of an electrical network of impedance elements [note 2] which presents the same impedance between all pairs of terminals [note 10] as did the given network. This article describes mathematical transformations between some passive, linear impedance networks commonly found in electronic circuits.
For example, in order to match an inductive load into a real impedance, a capacitor needs to be used. If the load impedance becomes capacitive, the matching element must be replaced by an inductor. In many cases, there is a need to use the same circuit to match a broad range of load impedance and thus simplify the circuit design.
Blackman's theorem is a general procedure for calculating the change in an impedance due to feedback in a circuit. It was published by Ralph Beebe Blackman in 1943, [1] was connected to signal-flow analysis by John Choma, and was made popular in the extra element theorem by R. D. Middlebrook and the asymptotic gain model of Solomon Rosenstark.
This may be modeled by an ideal inductance element in series with a resistance. Circuit analysis using electric elements is useful for understanding practical networks of electrical components. Analyzing how a network is affected by its individual elements makes it possible to estimate how a real network will behave.
This follows from the fact the impedance of L and C elements are themselves simple rational functions and any algebraic combination of rational functions results in another rational function. This is sometimes referred to as the driving point impedance because it is the impedance at the place in the network at which the external circuit is ...
The characteristic impedance of an infinite transmission line at a given angular frequency is the ratio of the voltage and current of a pure sinusoidal wave of the same frequency travelling along the line. This relation is also the case for finite transmission lines until the wave reaches the end of the line. Generally, a wave is reflected back ...