Average Power in AC Circuit

In summary, average power in an AC circuit is the average rate at which energy is transferred from the source to the load over one complete cycle. It takes into account both the magnitude and direction of the power flow. It differs from instantaneous power, which refers to the power at a specific moment in time. The formula for calculating average power is P = Vrms x Irms x cos(θ), where Vrms is the root mean square voltage, Irms is the root mean square current, and θ is the phase angle between the voltage and current. The phase angle between the voltage and current can affect the average power, with a phase angle of 0 degrees resulting in maximum average power and a phase angle of 90 degrees resulting in
  • #1
Tekee
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Homework Statement



Given resistance of circuit 68 W, I(max) = .191 A, V(max) = 22.5, what is the average power of this circuit?

Homework Equations



P(avg) = I(avg)V(max)

The Attempt at a Solution



I took .191 and divided by sqrt(2) to get the rms current and multiplied by the max voltage 22.5. Not getting the right answer, though...
 
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  • #2
P(avg) = I(avg)V(max)
It should be
P(avg) = I(avg)V(avg)
 

1. What is average power in an AC circuit?

The average power in an AC circuit is the average rate at which energy is transferred from the source to the load over one complete cycle. It takes into account both the magnitude and direction of the power flow.

2. How is average power different from instantaneous power in an AC circuit?

Instantaneous power in an AC circuit refers to the power at a specific moment in time, while average power is the average of all instantaneous power values over one complete cycle. This means that average power takes into account the fluctuations in instantaneous power over time.

3. What is the formula for calculating average power in an AC circuit?

The formula for average power in an AC circuit is P = Vrms x Irms x cos(θ), where Vrms is the root mean square voltage, Irms is the root mean square current, and θ is the phase angle between the voltage and current.

4. How is average power affected by the phase angle in an AC circuit?

The phase angle between the voltage and current in an AC circuit can affect the average power. If the phase angle is 0 degrees (or cos(θ) = 1), the average power will be at its maximum value. However, if the phase angle is 90 degrees (or cos(θ) = 0), the average power will be 0.

5. Is average power always positive in an AC circuit?

No, average power can be both positive and negative in an AC circuit. This depends on the phase angle between the voltage and current. If the phase angle is positive (leading), the average power will be positive. If the phase angle is negative (lagging), the average power will be negative.

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