Diference between Vrms & ac value of a signal

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Discussion Overview

The discussion centers around the concept of Vrms (root mean square voltage) and its measurement in relation to AC signals. Participants explore the practical methods for measuring Vrms using instruments like voltmeters and oscilloscopes, as well as the distinction between RMS values and AC values of signals, including potential connections to heating effects.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant asks for clarification on what Vrms is and how it can be measured practically, questioning whether it is purely mathematical or if it can be directly measured like voltage.
  • Another participant explains that for a sinusoidal wave, various voltage measurements can be taken, including peak voltage and RMS voltage, noting that RMS voltage is typically what is measured with a multimeter.
  • A different participant suggests using an oscilloscope to measure peak voltage and then calculate the RMS value by multiplying the peak voltage by approximately 0.707, referencing a specific mathematical relationship.
  • A later reply expresses gratitude for the information provided by other participants.

Areas of Agreement / Disagreement

Participants provide various methods for measuring Vrms and discuss its relationship to AC signals, but there is no consensus on the broader implications or definitions of RMS versus AC values.

Contextual Notes

Some assumptions about the definitions of RMS and AC values may not be fully articulated, and the discussion does not resolve the potential connection between RMS values and heating effects.

sphyics
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What is Vrms value. How can i measure it practically with whatever instruments (read voltmeter, oscilloscope). is it some mathematical stuff or we can measure it directly as voltage is measured.


so please tell me the difference between rms value and ac value of a signal, is rms value releated to some heating effect...
 
Last edited:
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For a sinusoidal wave, you can measure peak voltage, peak-to-peak voltage, average voltage over a half-cycle, or effective (http://en.wikipedia.org/wiki/Root_mean_square" ) voltage. RMS voltage of an ac source is usually what you will measure with your hand-held multimeter.
 
Last edited by a moderator:
You could also use your oscilloscope, read the peak voltage and multiply by 0.707 (or more specifically, by [itex]\sqrt {2}/2[/itex]). If you take a look at this page it may clarify the meaning for you.
 
thanks dlgoff, Ouabache for the valuable informations.
 

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