- #1

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Actually, I faced this question in a recent examination. Though I ansewered (v), now I think the right answer would be square wave, as it grabs the maximum magnitude for more duration of time than the others. Am I right?

Thanks.

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- Thread starter samieee
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- #1

- 67

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Actually, I faced this question in a recent examination. Though I ansewered (v), now I think the right answer would be square wave, as it grabs the maximum magnitude for more duration of time than the others. Am I right?

Thanks.

- #2

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http://en.wikipedia.org/wiki/Root_mean_square#Average_electrical_power

Then you can compare the RMS values of your different waveforms:

http://en.wikipedia.org/wiki/Root_mean_square#RMS_of_common_waveforms

- #3

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- #4

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Right, so your intuition with regards to the square wave was spot on.

The instantaneous power delivered to the resistor is ##p(t) = R i(t)^2##. If you try to imagine the graph of ##p(t)## for your waveforms, it should confirm your idea of why its average value is highest in the case of the square wave.

- #5

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This question cannot really be answered as stated here. Are the amplitudes of all the waves supposed to be the same? That needs to be specified.Suppose there are some waveforms to be used as current input: i)sine wave ii)square wave iii) triangle wave iv)sawtooth wave and v)sawtooth wave with both the cycles(+ve half cycle and -ve half cycle) in positive Y axis. Which wave will generate more heat?

- #6

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Are the amplitudes of all the waves supposed to be the same? That needs to be specified.

Yes, amplitudes of all the waves are same.

- #7

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Okay. So yes, it is the square wave. As milesyoung said, you need to consider [itex]i^2 R[/itex].

- #8

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Also assuming the loads are the same.

- #9

KHMOU YOUSSEF

All the signals have the same frequency?

- #10

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Yes.Also assuming the loads are the same.

That does not matter. The average ofAll the signals have the same frequency?

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- #12

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- #13

NascentOxygen

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That's the beauty of the RMS value, it directly relates to the heating value (in a resistive load).Suppose there are some waveforms to be used as current input: i)sine wave ii)square wave iii) triangle wave iv)sawtooth wave and v)sawtooth wave with both the cycles(+ve half cycle and -ve half cycle) in positive Y axis. Which wave will generate more heat?

- #14

NascentOxygen

Staff Emeritus

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Wouldn't frequency-doubling lasers allow you to generate some coherent harmonics?

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