Search results
Results from the WOW.Com Content Network
Admittance Y, measured in siemens, is defined as the inverse of impedance Z, measured in ohms: Y ≡ 1 Z {\displaystyle Y\equiv {\frac {1}{Z}}} Resistance is a measure of the opposition of a circuit to the flow of a steady current, while impedance takes into account not only the resistance but also dynamic effects (known as reactance ).
The SI unit of impedance is the ohm with the symbol of the upper case Greek letter omega (Ω) and the SI unit for admittance is the siemens with the symbol of an upper case letter S. Normalised impedance and normalised admittance are dimensionless. Actual impedances and admittances must be normalised before using them on a Smith chart.
In electrical engineering, susceptance (B) is the imaginary part of admittance (Y = G + jB), where the real part is conductance (G). The reciprocal of admittance is impedance (Z = R + jX), where the imaginary part is reactance (X) and the real part is resistance (R). In SI units, susceptance is measured in siemens (S).
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]
If a new pair of impedance and admittance is added in front of the network, its input impedance remains unchanged since the network is infinite. Thus, it can be reduced to a finite network with one series impedance Z {\displaystyle \ Z\ } and two parallel impedances 1 / Y {\displaystyle \ 1/Y\ } and Z IT . {\displaystyle \ Z_{\text{IT}}~.}
Admittance parameters or Y-parameters (the elements of an admittance matrix or Y-matrix) are properties used in many areas of electrical engineering, such as power, electronics, and telecommunications. These parameters are used to describe the electrical behavior of linear electrical networks.
Any 2-port S-parameter may be displayed on a Smith chart using polar co-ordinates, but the most meaningful would be and since either of these may be converted directly into an equivalent normalized impedance (or admittance) using the characteristic Smith Chart impedance (or admittance) scaling appropriate to the system impedance.
A per-unit system provides units for power, voltage, current, impedance, and admittance. With the exception of impedance and admittance, any two units are independent and can be selected as base values; power and voltage are typically chosen. All quantities are specified as multiples of selected base values.