impedance, however, does not equal the sum of resistance and reactance.
What is the impedance if the voltage of the line is 115 volts?
The impedance of its secondary will be a quarter of this or 3,000 ohms.
The impedance of the coil I is changed by moving its adjustable core.
impedance depends chiefly upon the frequency of alternation.
An important factor in the design of impedance coils is the grade of iron used in the magnetic circuit.
The usual diagrammatic symbol for an impedance coil is shown in Fig. 106.
The symbol of Fig. 104 is a good one for the toroidal type of impedance coil.
These four impedance coils are wound on separate cores and do not have any inductive relation whatsoever with each other.
In order to further increase the impedance, the cores are made long and heavy.
impedance A measure of the opposition to the flow of alternating current through a circuit. Impedance is measured in ohms. The resistance of a circuit to direct current (also measured in ohms) is generally not the same as its impedance, due to the effects of capacitance and induction in and among the components of the circuit. See also impedance matching. |
A measure of the apparent resistance posed by an electrical circuit to an alternating current (AC).
Note: The term impedance is most often encountered in dealing with antennas and speakers in television, stereo, and radio systems.