Real vs Average Power: Which is Correct?

Thread starter influx
Start date Feb 17, 2014
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Average Power

In summary, real power is the actual power consumed by a device or system, while average power is the average amount of power consumed over a specific period of time. Real power takes into account both magnitude and phase difference, while average power only considers magnitude. Both measurements are accurate but serve different purposes - real power for exact energy consumption and average power for understanding consumption patterns. Real power should be used for specific moment calculations, while average power is useful for energy costs and usage trends. Real and average power can be the same in purely resistive circuits, but in most circuits they will differ due to reactive components. Both can be measured using a wattmeter or calculated using voltage and current measurements.

Feb 17, 2014

influx

So I was reading through my course's lecture slides and it appears to contradict.

In one slide it states that the average power, P = V_rmsI_rmsCos(phi)

in another slide it states that the real power, P = V_rmsI_rmsCos(phi)

Which one is correct?

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Feb 17, 2014

FOIWATER

Gold Member

Since the rms value is the average value, and they are used to calculate real power.. the equation is calculating average real power

1. What is the difference between real and average power?

Real power is the actual power consumed by a device or system, which is measured in watts. Average power, on the other hand, is the average amount of power consumed over a specific period of time, and is also measured in watts. Real power takes into account both the magnitude and phase difference between voltage and current, while average power only considers the magnitude.

2. Which one is more accurate, real or average power?

Both real and average power are accurate measurements, but they serve different purposes. Real power is used to calculate the actual energy consumed by a device, while average power is useful for understanding overall power consumption patterns over a period of time.

3. When should I use real power and when should I use average power?

Real power should be used when you need to know the exact amount of power consumed by a device at a specific moment. Average power is useful for calculating energy costs and understanding power usage trends over time.

4. Can real and average power be the same?

In some cases, real and average power can be the same. This is typically seen in purely resistive circuits, where there is no phase difference between voltage and current. However, in most circuits, real and average power will be different due to the presence of reactive components.

5. How do I measure real and average power?

Real and average power can be measured using a wattmeter, which is a device that measures both voltage and current and calculates the power using the formula P = VI cos(θ), where θ is the phase difference between voltage and current. Alternatively, you can also use an oscilloscope and a multimeter to measure voltage and current separately and calculate the power using the same formula.