13.4 Inductance

Describe the physical and electrical properties of an inductor.

• Inductance is the tendency of a conductor to oppose a change in electrical current.
  • i. Inductance of a conductor depends on the physical properties of the conductor. Straight wires are typically modeled as having zero inductance.
  • ii. An inductor, such as a solenoid, is a circuit element that has significant inductance.
  • iii. The inductance of a solenoid is dependent on the total number of turns, the length of the solenoid, the cross-sectional area of the solenoid, and magnetic permeability of the solenoid’s core. Relevant equation: µ NA2 Lsol = core 
• Inductors store energy in the magnetic field that is generated by current in the inductor. Relevant equation: 1ULL =I 2 2
  • i. The energy stored in the magnetic field generated by an inductor in which current is flowing can be dissipated through a resistor or used to charge a capacitor. TOPIC 13.4 Inductance
  • ii. The transfer of energy generated in an inductor to other forms of energy obeys conservation laws.
• By applying Faraday’s law to an inductor and using the definition of inductance, induced emf can be related to inductance and the rate of change of current. Relevant equation: dIEi =−L dt