# Inductors Inductors

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Inductors
Peter Mathys
ECEN 1400
Inductors
• An inductor is a passive element that can store
energy in its magnetic field.
• Two examples: Solenoidal (left) and toroidal
(right) 100 μH inductors.
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i-v Relationship for L
• Inductance L is measured in henry (H). Typical
values range from μH (10-6 H) to about 1 H.
Inductance of Solenoid L
• Single layer of N turns of wire on core material
with permeability μ. Length l (ell) and crosssection A.
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Power and Energy
• Inductor does not dissipate power.
• Inductor can store energy =&gt; has memory.
Inductors in Series
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Inductors in Parallel
L and Sinusoidal Signals
• Since vL(t) = L&middot;diL(t)/dt, inductors are short
circuits for dc =&gt; Cannot measure i-v
characteristic using dc signals.
• Try setting iL(t) = IA&middot;cos(ωt) where IA is the
amplitude of iL(t) and ω=2πf is the frequency
in radians/sec (f is frequency in Hz or sec-1).
• Then observe vL(t) for different values of IA
and ω (or f).
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Inductors and Sinusoids
Graphically
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Compare to Capacitor
Using Complex Numbers
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Impedance of L
Series R,L,C Circuit
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Parallel R,L,C Circuit
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```