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e-n-i-g-m-a
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#1
Report Thread starter 14 years ago
#1
For resistance in parallel, the equivalent resistance is always smaller than the smallest resistance and for resistance in series, the equivalent resistance is always larger than the larger resistance. why is this so ???
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jpowell
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#2
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#2
Because of the way you sum resistances. In series R = r1 + r2 + r3, whereas in parallel 1/R = 1/r1 + 1/r2 + 1/r3

Now in the first case the sum of a load of positive numbers is always going to be bigger than the largest one. In the second case the inverse of a sum of positive numbers is always going to be smaller than the largest, and the largest inverse is the smallest resistance.
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Ben C
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#3
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Or to put it another way, if you think of a resistor like a narrow path which the current has to get through, then a series path is long and hard to pass through, whereas with parallel, two paths side by side are easier than one.
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r0manticide17
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#4
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tis a long worded question. cut out the waffle, get a good revision guide, or read your notes again. Or then again you could get the geniuses on here to do it for you
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