self-induction
self-in·duc·tion
(sĕlf′ĭn-dŭk′shən)self-induction
self′-induc′tion
n.
Noun | 1. | self-induction - generation of an electromotive force (EMF) in a circuit by changing the current in that circuit; usually measured in henries |
单词 | self-induction | |||
释义 | self-inductionself-in·duc·tion(sĕlf′ĭn-dŭk′shən)self-inductionself′-induc′tionn.
Self-Inductionself-induction[¦self in¦dək·shən]Self-Inductionthe appearance of an electromotive force (emf) of induction in a conducting circuit when the current in the circuit changes. This phenomenon is a special case of electromagnetic induction. The current change in the circuit causes a change in the magnetic flux through the surface enclosed by the circuit. As a result, an emf—the emf of self-induction—is induced in the circuit. The direction of the emf is determined by Lenz’s law: if the current in the circuit increases, the emf of self-induction opposes this increase; if the current decreases, the emf opposes the decrease. Thus, self-induction is similar to the phenomenon of inertia in mechanics. The emf of self-induction eL is proportional to the rate of change of the current i and to the self-inductance L of the circuit: eL = - Ldi/dt. Because of self-induction, the closing of an electric circuit containing a constant emf does not instantaneously establish a steady current; the current is established only after a certain time interval (see TRANSIENT). Similarly, when the circuit is opened, the current flow does not cease instantaneously. The emf of self-induction that is induced by the opening of the circuit can be several times greater than the emf of the source. In AC circuits, the emf of self-induction causes the current in an inductance coil to lag in phase behind the voltage across the ends of the coil by (see ALTERNATING CURRENT). The phenomenon of self-induction plays an important role in electrical engineering and radio engineering. Self-induction causes the recharging of a capacitor connected in series with an inductance coil (see OSCILLATORY CIRCUIT); as a result, natural electromagnetic oscillations are established in the circuit. REFERENCEKalashnikov, S. G. Elektrichestvo. Moscow, 1970. (Obshchii kurs fiziki, vol. 2.)G. IA. MIAKISHEV self-induction
Words related to self-induction
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