3/27/2013
AC Circuits
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Resistors in AC Circuits
V=IR
V =I R
RMS
RMS
There’s an AC Circuit!?
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3/27/2013
Resistors in AC Circuits
v  Vmax sin 2fft
Resistors in AC Circuits
Phase
The degree to which the minimum and maximum differ from each other.
Resistor -10.0 Ω
Source Vrms - 10.0
10 0 V
∆VR - ___________
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Resistors in AC Circuits
The output voltage of an AC generator is given by ∆v=(170V)sin(60πt) . The generator is connected across a 20.0‐Ω resistor. By inspection, what are the (a) maximum voltage and (b) frequency? Find the (c) rms voltage across the resistor, (d) rms current in the resistor, (e) maximum current in the resistor, and (f) power delivered to the resistor. (g) Should the argument of the sine function be in degrees or radians? Compute the current when t=0.0050s.
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Capacitors in DC Circuits
What Happens?
Current exists but slows down until the capacitor has the same voltage as the battery.
Capacitors in AC Circuits
What Happens?
What Happens?
Current never stops since it changes direction, but the capacitor resists the current.
Capacitors in AC Circuits
When does a capacitor have its largest charge (and voltage) in a circuit?
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Capacitors in AC Circuits
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Xc 
2fC
C=0.10 Farads
V  IR
Capacitors in AC Circuits
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Inductors in DC Circuits
What Happens?
When current changes the inductor produces a back EMF.
Inductors in AC Circuits
What Happens?
What Happens?
Current is always changing therefore the inductor is always creating a back (or resistive) EMF.
Inductors in AC Circuits
When does a inductor create the largest back EMF?
vL  L
I
t
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Inductors in AC Circuits
Inductors in AC Circuits
X L  2ffL
L=50 Henries
V  IR
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RLC Circuits
RLC Circuits
Inductor
Capacitor
Resistor
AC Source
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RLC Circuits
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