INDUCTANCE

DC Circuits INDUCTANCE INDUCTANCE Experiments investigating the unique behavioral characteristics of inductance led to the invention of the transformer. EO 1.1 DESCRIBE how current flow, magnetic field, and stored energy in an inductor relate to one another. EO 1.2 DESCRIBE how an inductor opposes a change in current flow. EO 1.3 Given a circuit containing inductors, CALCULATE total inductance for series and parallel circuits. EO 1.4 Given an inductive resistive circuit, CALCULATE the time constant for the circuit. Inductors An inductor is a circuit element Figure 1 Induced EMF that will store electrical energy in the form of a magnetic field. It is usually a coil of wire wrapped around a core of permeable material. The magnetic field is generated when current is flowing through the wire. If two circuits are arranged as in Figure 1, a magnetic field is generated around Wire A, but there is no electromotive force (EMF) induced into Wire B because there is no relative motion between the magnetic field and Wire B. If we now open the switch, the current stops flowing in Wire A, and the magnetic field collapses. As the field collapses, it moves relative to Wire B. When this occurs, an EMF is induced in Wire B. Rev. 0 Page 1 ES-03