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# 14: Inductance

In this chapter, we look at the applications of inductance in electronic devices and how inductors are used in circuits

• 14.1: Prelude to Inductance
o far, we have discussed some examples of induction, although some of these applications are more effective than others. The smartphone charging mat in the chapter opener photo also works by induction. Is there a useful physical quantity related to how “effective” a given device is? The answer is yes, and that physical quantity is inductance. In this chapter, we look at the applications of inductance in electronic devices and how inductors are used in circuits
• 14.2: Mutual Inductance
Inductance is the property of a device that tells us how effectively it induces an emf in another device. It expresses the effectiveness of a given device. When two circuits carrying time-varying currents are close to one another, the magnetic flux through each circuit varies because of the changing current in the other circuit. Consequently, an emf is induced in each circuit by the changing current in the other. This type of emf is therefore called a mutually induced emf, and the phenomenon is
• 14.3: Self-Inductance and Inductors
Mutual inductance arises when a current in one circuit produces a changing magnetic field that induces an emf in another circuit. But can the magnetic field affect the current in the original circuit that produced the field? The answer is yes, and this is the phenomenon called self-inductance.
• 14.4: Energy in a Magnetic Field
The energy of a capacitor is stored in the electric field between its plates. Similarly, an inductor has the capability to store energy, but in its magnetic field. This energy can be found by integrating the magnetic energy density,
• 14.5: RL Circuits
A circuit with resistance and self-inductance is known as an RL circuit.
• 14.6: Oscillations in an LC Circuit
Both capacitors and inductors store energy in their electric and magnetic fields, respectively. A circuit containing both an inductor (L) and a capacitor (C) can oscillate without a source of emf by shifting the energy stored in the circuit between the electric and magnetic fields. These concepts are applicable to the exchange of energy between the electric and magnetic fields in electromagnetic waves. We consider an idealized circuit of zero resistance in an LC circuit.
• 14.7: RLC Series Circuits
When the switch is closed in a RLC circuit, the capacitor begins to discharge and electromagnetic energy is dissipated by the resistor at a specific rate .