Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I have 2 equation describing the alternating amperage $I_1$ and $I_2$. I need to get amount of these amperages.

My equations: $$I_1=10\sin(\omega t+30)$$ $$I_2=20\sin(\omega t-50)$$

How can i make it? I forgot.

Thank you.

share|improve this question

closed as too localized by Qmechanic Feb 15 '13 at 15:29

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Please don't post your homework, if that's what this is. Otherwise, it's unclear to me what you're asking. –  Mark Eichenlaub Nov 14 '10 at 6:28
    
@shk: do you need to add i1 and i2 and reduce to the shortest form? –  Peter Mortensen Nov 14 '10 at 10:13
4  
Better always use "current" instead of "amperage", especially on a physics site. –  Peter Mortensen Nov 14 '10 at 10:19
    
I am not sure what you are really asking here. Do you just want the R.M.S. current? –  Noldorin Nov 14 '10 at 16:06
    
What's wrong with "amperage"? dictionary.reference.com/browse/amperage –  endolith Nov 15 '10 at 17:01

1 Answer 1

up vote 2 down vote accepted

I am going to assume that you ask R.M.S. current and will answer that. If you want some other form of answer just clarify the question a bit more and I'll adjust the answer.

To calculate the RMS(Root-Mean-Square) value of a current, you do the following calculation:

$\sqrt{\frac{1}{T} \int_0^T i(t) dt }$

where T is the period of the signal and t is the variable of integration.

share|improve this answer
    
Oh let me note that you can apply superposition to add both RMS values up, provided that your circuitry is linear. –  Cem Nov 17 '10 at 12:35

Not the answer you're looking for? Browse other questions tagged or ask your own question.