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UNIVERSITY OF NEBRASKA-LINCOLN
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No.
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No.
Fill in this call number for our section: 6348
634
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1 3 5 7 9 11 13 15 17 19
Class Averages(3 exams w/bonus points
and homework quizzes)
average
70.4
+ 9590
- 85+ 80
75- 70+ 65
60- 55+ 50
45- 40
These cutoffswill not beraised…youcan use themto determineyour guaranteedlowest grade.
35 40 45 50 55 60 65 70 75 80 85 90 95 100
+-
The switch is closed on this simple circuit of an electromagnet:
time
What might affect how rapidly current reaches its maximum value?
I = V/Rtime switch
is closed
The act of discharging through an inductor creates a
short-lived electromagnet.
But rather than vanishing immediatelythe strength of the electromagnet fades slowly as an induced voltage
tries to sustain the current a little longer!
Discharging through an inductor should slow the process down:
Remember the inductor slows down bothturn-on and the turn-off.
Fully charged capacitor
Current starts
to flow
+ + + +
– – – –
+ +
– –
I
I
I
I
I Maximum
current
Maximumpositive current
Capacitor fully charged
Current flows (opposite direction!)
+ + + +
– – – –
I
+ +
– –
I
+ +
– – I
Current begins to die down
I
I
OscillatorsFully charged capacitor
Energy: all E
+ + + +
– – – –
Capacitor charged
Energy: all E
Current starts to flowEnergy: some E, some B
Maximum current
Energy: all B
Current begins to die downinduced
C charges in opposite direction
Energy: some E, some B
Current flows (opposite direction!)
Energy: some E, some B
+ + + +
– – – –
+ +
– –
I
I I
I
+ +
– –
+ +
– –
Frequency
A single loop:A small surfacearea capacitor
size ofinductor
size ofcapacitor
1
A specially shaped metal “C”:
smallinductance
coil
tinycapacitor
2.45 GHz
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