PHYS 102

1
PHYS 102

• Alternating Current (AC) circuits. So far we
  have been talking about Direct Current.

2
PHYS 102

• Time varying currents can be produced by time
  varying voltages. (Like that supplied by the
  wall socket)
• Recall need to identify amplitude, frequency,
  and phase constant for sinusoidal functions.

3
PHYS 102

• We restrict our discussion to sinusoidally
  varying currents.

4
PHYS 102

• Does it make sense to talk about averages?

To discuss averages for sinusoidal functions, one
would obtain a value of zero! Yet, the wall
socket value of 120V is a type of average.
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PHYS 102

• Does it make sense to talk about averages?
• Answer YES! (But we need to discuss a root mean
  square average).

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PHYS 102
Root mean square (RMS)
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PHYS 102

• Where

T is the period of oscillation.