#### daveleonard

##### Member

I know the answer is 240 uf but what I need to know is how to figure that. The math involved so I can reasonably answer a test question with different values. Thanks.

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I know the answer is 240 uf but what I need to know is how to figure that. The math involved so I can reasonably answer a test question with different values. Thanks.

1/400 +1/600 = 1/answer

1/400 = .0025

1/600 = .00166666667

.0025 + .00166666667 = .004166666667

1/.00416666667 = 240 (well 239.999999 (rounding here...))

400x600 240000

---------- = --------- = 240

400+600. 1000

---------- = --------- = 240

400+600. 1000

Mike, you cheat. But that only works for two. Sum of the reciprocals always works with any number of caps in series (or resistance, inductance in parallel).400x600 240000

---------- = --------- = 240

400+600. 1000

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Well, since he only asked about two, I figured I would give him the fastest way to the answer.

D

How did the OP know the result without knowing the math?

Thanks all. I'll use reciprocal when more than two.

D

Good for you! We need new hams who actually understand the theory and rules. Keep on asking and learning.

Do any of the ham clubs near you offer licensing classes? Could be a big help if available for you.

Thanks again, 73's Dave

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