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Should the batteries be treated differently than resistors when it come to power dissipation?

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- Thread starter abdo799
- Start date

- #1

- 169

- 4

Should the batteries be treated differently than resistors when it come to power dissipation?

- #2

sophiecentaur

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If you want to do it that way, that's fine. Input V and total R gives current. Then Isquared times the appropriate R gives the power dissipated in the resistor.

Sometimes it's good to calculate things in more than one way and feel smart when you get the same answer each time.

- #3

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i have this problem where there are 3 batteries in parallel

If you want to do it that way, that's fine. Input V and total R gives current. Then Isquared times the appropriate R gives the power dissipated in the resistor.

Sometimes it's good to calculate things in more than one way and feel smart when you get the same answer each time.

and one resistor , to calculate the power dissipation i used this formula from this site ( http://farside.ph.utexas.edu/teaching/302l/lectures/node62.html )(V^2*r/(r+R)^2)

will that work ? can i simply replace the r+R in his formula by the total resistance of the circuit?

- #4

sophiecentaur

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The rigorous way to approach it would be to do the whole thing with different emfs and internal resistances r1, r2 and r3. This more complicated circuit can be tackled using Kirchoff's Laws 1 and 2. Personally, I reckon that's a bit over the top but it would be interesting if you wanted to know what happens when one battery goes soggy first (imagine a standby system, after years of use)

- #5

- 169

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The rigorous way to approach it would be to do the whole thing with different emfs and internal resistances r1, r2 and r3. This more complicated circuit can be tackled using Kirchoff's Laws 1 and 2. Personally, I reckon that's a bit over the top but it would be interesting if you wanted to know what happens when one battery goes soggy first (imagine a standby system, after years of use)

I will begin my calculations and post them, gonna post a new thread in homework section, thank you

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