where Z = impedance, W; R = resistance, W; L = inductance, H; XL = inductive reactance, W; XC = capacitive reactance, W; and q = phase angle, degrees, by which current leads voltage in a capacitive circuit or lags voltage in an inductive circuit (0° indicates an in-phase condition). Resonant Frequency When an inductor and capacitor are connected in series or parallel, they form a resonant circuit. The resonant frequency can be determined from the equation | where Z impedance W R resistance W L inductance H XL inductive reactance W XC capacitive reactance W and 0 phase angle degrees by which current leads voltage in a capacitive circuit or lags voltage in an inductive circuit 0 indicates an in-phase condition . Resonant Frequency When an inductor and capacitor are connected in series or parallel they form a resonant circuit. The resonant frequency can be determined from the equation f T 2 rcV LC 1 2 pCXC X. 2 pL where f frequency Hz L inductance H C capacitance F and XL XC impedance W. The resonant frequency can also be determined through the use of a reactance chart developed by the Bell Telephone Laboratories Fig. . This chart can be used for solving problems of inductance capacitance frequency and impedance. If two of the values are known the third and fourth values may be found with its use. Defining Terms Air capacitor A fixed or variable capacitor in which air is the dielectric material between the capacitor s plates. Ambient temperature The temperature of the air or liquid surrounding any electrical part or device. Usually refers to the effect of such temperature in aiding or retarding removal of heat by radiation and convection from the part or device in question. Ampere-turns The magnetomotive force produced by a coil derived by multiplying the number of turns of wire in a coil by the current A flowing through it. Anode The positive electrode of a capacitor. Capacitive reactance The opposition offered to the flow of an alternating or pulsating current by capacitance measured in ohms. Capacitor An electrical device capable of storing electrical energy and releasing it at some predetermined rate at some predetermined time. It consists essentially of two conducting surfaces electrodes separated by an insulating material or dielectric. A capacitor stores electrical energy blocks the flow of direct current and permits the flow of alternating current to a degree dependent essentially upon capacitance and .
