1. Inductive Reactance

2. Inertial Mass  Acceleration of water in a pipe requires force to move a mass.  An inductor creates an emf proportional to a change in current. Magnetic field in the coil  The field acts as a mass that reduces change in the current. A)vA)v i L

3. Inductor Alone  An AC source provides a sinusoidal voltage. Inductor matchesInductor matches One loop circuitOne loop circuit  The inductor voltage varies with the current.  The voltage is related to the rate of change of the current. L v

4. Phase Shift  Voltage and current are not in phase through an inductor. Voltage leads current: ELI the ICE manVoltage leads current: ELI the ICE man

5. Ohm for Inductors  The amplitude of voltage and current through an inductor are related.  The ratio gives an expression like Ohm’s law.  This is the inductive reactance. Measured in ohmsMeasured in ohms v

6. Frequency Dependent  Inductive reactance depends linearly on frequency. Low reactance at low frequency High reactance at high frequency  DC has no inductive reactance. Equal to zero frequency f XLXL

7. Different Response  Inductors and capacitors react differently with changes to frequency. Resistors stay the sameResistors stay the same  Consider reactances that are equal at a frequency ω 0. Capacitive reactance higher for low frequencyCapacitive reactance higher for low frequency Inductive reactance higher for high freqencyInductive reactance higher for high freqency

8. Resistance vs Reactance  Resistance is measured in ohms.  Resistance doesn’t depend on frequency.  Resistance doesn’t affect the phase.  Reactance is measured in ohms.  Reactance depends on frequency. 1/  C or  L  Reactance shifts the phase. ELI the ICE man next