What Is the Correct RMS Voltage Calculation for a Sinewave?

In summary, the question is asking for the RMS voltage of the top wave, which can be calculated by finding the square root of the average of the squared values of the waveform. The correct answer is 0.707 V. The peak voltage of 1V is not relevant in this calculation.
  • #1
shaqtus
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0

Homework Statement


[PLAIN]http://img16.imageshack.us/img16/7396/oscf.jpg

What is the RMS voltage of the top wave?

Homework Equations


RMS... root mean square


The Attempt at a Solution


If I'm right, the peak voltage is 1 V (gotten from 2 * 500mV). Square of 1 is 1. And there are 4 peaks, so 1 + 1 + 1 + 1 = 4. Mean is 4 / 4 = 1. Then sqrt of 1 is 1. So my final answer is 1 V. Is this right?
 
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  • #2
It looks to me like the top wave is plotted at 1V/division. Isn't that what this bit implies:

attachment.php?attachmentid=40033&stc=1&d=1318721845.gif
 

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  • #3
shaqtus said:
What is the RMS voltage of the top wave?
I assume this is a sinewave. Have you studied the RMS value of a sinewave? If not, then use a google search.

The Attempt at a Solution


If I'm right, the peak voltage is 1 V (gotten from 2 * 500mV). Square of 1 is 1. And there are 4 peaks, so 1 + 1 + 1 + 1 = 4. Mean is 4 / 4 = 1. Then sqrt of 1 is 1. So my final answer is 1 V. Is this right?
No. Not even close, I'm afraid.
 

Related to What Is the Correct RMS Voltage Calculation for a Sinewave?

1. What is an oscillogram?

An oscillogram is a graph that represents the variation of an electrical signal over time. It plots the amplitude of the signal on the vertical axis and time on the horizontal axis.

2. What is RMS voltage?

RMS (Root Mean Square) voltage is a measure of the average voltage of an alternating current (AC) signal. It takes into account the varying amplitude of the signal and calculates the equivalent DC voltage that would produce the same amount of heat in a resistor as the AC signal.

3. How is RMS voltage calculated?

RMS voltage is calculated by taking the square root of the mean of the squares of the voltage values over a specific period of time. This is represented by the equation Vrms = √(1/T ∫(t1 to t2) V(t)^2 dt), where T is the period of time and V(t) is the instantaneous voltage at time t.

4. What is the difference between peak voltage and RMS voltage?

Peak voltage is the maximum voltage value reached by an AC signal, while RMS voltage is the equivalent DC voltage that would produce the same amount of heat in a resistor. Peak voltage does not take into account the varying amplitude of the signal, while RMS voltage does.

5. Why is RMS voltage used instead of peak voltage?

RMS voltage is a more accurate measure of the voltage of an AC signal. It takes into account the varying amplitude of the signal and provides a more meaningful measurement for the power and energy calculations in AC circuits. Additionally, many electronic devices are designed to operate based on the RMS voltage, making it a more practical and relevant measurement in the field of electrical engineering.

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