Chap30_PHY2049 - Chapter 30 – Inductance Mutual...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 30 – Inductance- Mutual Inductance- Self-Inductance and Inductors- Magnetic-Field Energy- The R-L Circuit- The L-C Circuit- The L-R-C Series Circuit 1. Mutual Inductance- A changing current in coil 1 causes B and a changing magnetic flux through coil 2 that induces emf in coil 2. dt d N B 2 2 2 Φ- = ε 1 21 2 2 i M N B = Φ 1 2 2 21 1 21 2 i N M dt di M B Φ = →- = ε dt di M dt d N B 1 21 2 2 = Φ Magnetic flux through coil 2: Mutual inductance of two coils: M 21 M 21 is a constant that depends on geometry of the coils = M 12 . dt di M dt di M 2 1 1 2- =- = ε ε 2 1 1 1 2 2 i N i N M B B Φ = Φ =- If a magnetic material is present, M 21 will depend on magnetic properties. If relative permeability (K m ) is not constant (M not proportional to B) b Φ B2 not proportional to i 1 (exception). Ex. 30.1 Mutual inductance: emf opposes the flux change- Only a time-varying current induces an emf. Units of inductance: 1 Henry = 1 Weber/A = 1 V s/A = 1 J/A 2 2. Self Inductance and Inductors i N L B Φ = dt di L dt d N B = Φ dt di L- = ε- When a current is present in a circuit, it sets up B that causes a magnetic flux that changes when the current changes b emf is induced. Lenz’s law : a self-induced emf opposes the change in current that caused it b Induced emf makes difficult variations in current. Self-inductance Self-induced emf dt di L l d E n- = ∫ a a Inductors as Circuit Elements Inductors oppose variations in the current through a circuit. -In DC-circuit, L helps to maintain a steady current (despite fluctuations in applied emf). In AC circuit, L helps to suppress fast variations in current.- Reminder of Kirchhoff’s loop rule: the sum of potential differences around any closed loop is zero because E produced by charges distributed around circuit is conservative E c ....
View Full Document

This note was uploaded on 07/30/2011 for the course PHY 2049 taught by Professor Saha during the Spring '08 term at University of Central Florida.

Page1 / 22

Chap30_PHY2049 - Chapter 30 – Inductance Mutual...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online