### AC circuits

```Announcements
Be sure to fill out the online course evaluations
HW 12 is now due FRIDAY DEC 9th, 8AM
HW 13 is now due TUESDAY DEC 12th, 8AM
Today, we will cover the rest of the lecture for B
Week 12 AND the entire
lecture for Week 13.
Recitations next week will cover problems from HW 12 and HW 13
A
Lecture next week will cover (a) problems from HW 13 (if any are left). We
will also begin reviewing for the final exam.
Recitation on Monday Dec 12th will also be a review for final
C
ICLICKER QUESTION #0
Option Review for the Final exam will be on MONDAY Dec 19th at the following
time:
A) 8:30-11AM
B) 11:30-2pm
C) 2:30-5pm
B
D) None of these times are good, I would prefer a different day.
A
C
Show Active Figure 33.3 of Phasor
Clicker Question #1
Consider the voltage phasor in Figure 33.4, shown at
three instants of time. Choose the part of the figure
that represents the instant of time at which the
instantaneous value of the voltage has the largest
magnitude.
Figure 33.4
1. (a)
2. (b)
3. (c)
C
RMS current
Current LAGS Voltage in Inductor
Show Active Figure 33.6
Clicker Question #2
Consider the AC circuit in Figure 33.8. The
frequency of the AC source is adjusted while
its voltage amplitude is held constant. When
does the light bulb glow the brightest?
Figure 33.8
1.
2.
3.
It glows brightest at high
frequencies.
It glows brightest at low
frequencies.
The brightness is the same at all
frequencies.
Current LEADS voltage in a Capacitor
Show Active Figure 33.10
Clicker Question #3
Consider the AC circuit in Figure 33.12.
The frequency of the AC source is adjusted
while its voltage amplitude is held
constant. When
does the light bulb glow
B
the brightest?
Figure 33.12
1.
2.
3.
It glows brightest at high
frequencies.
It glows brightest at low
frequencies.
The brightness is the same at all
frequencies.
A
C
RLC Series Circuit
Phase Relation of various voltages
Clicker Question #4
Label each part of Figure 33.16, (a), (b), and (c), as
representing XL > XC, XL = XC, or XL < XC. Describe figure
(a).
Figure 33.16
1. XL > XC
2. XL = XC
3. XL < XC
HINT:
C
Clicker Question #5
What is the impedance of a series RLC
circuit at resonance?
1.
2.
3.
4.
larger than R
less than R
equal to R
impossible to
determine
Z 
R  ( L  c )
2
2
Transformer can “step up” or “step down” the voltage.
B
A
C
```