Capacitance and voltage relationship

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The discussion revolves around the calculation of the actual capacitance value of a capacitor ordered by Rahal, which is stated as 1000 µF with a variance of -10% to +50%. The correct range for the capacitance is determined to be 900 µF as the minimum and 1500 µF as the maximum. Confusion arises regarding whether the variance applies to voltage or capacitance, but it is clarified that the percentages pertain to the capacitance value. The importance of understanding the maximum voltage rating of the capacitor is also highlighted, as it indicates the limits for safe operation. Ultimately, the discussion emphasizes the need to accurately interpret the specifications provided by the manufacturer.
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Homework Statement



The actual value of the capacitor Rahal will receive may be different from the value the
catalogue states. The manufacturer guarantees that the maximum percentage difference
below/above the catalogue value will be –10% / +50%. Rahal orders one of the 400 V 1000 µF capacitors. Within what range will its actual value lie?

Homework Equations



Q=CV
therefore C is inversely proportional to V

The Attempt at a Solution



I would say:
1100µF = max
500µF = min

BUT THE ANSWER IS
900µF = min
1500µF = max

WHY?

thanks
 
Last edited:
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The stated capacitance is 1000.

The possible variance is -10% to +50%.

What is 10% of 1000 subtracted from 1000?
What is 50% of 1000 added to one thousand?
 
Martinet said:
The stated capacitance is 1000.

The possible variance is -10% to +50%.

What is 10% of 1000 subtracted from 1000?
What is 50% of 1000 added to one thousand?

but the variance is for the voltage...
 
jsmith613 said:
but the variance is for the voltage...

Where is that stated?
If so, why is the answer given farads?

Additionally, bearing in mind that I'm yet to study capacitors in any level of detail, does the voltage not correspond to a maximum input voltage that the device can handle without being damaged, destroyed, or at least cease to function?
 
Martinet said:
Where is that stated?
If so, why is the answer given farads?

Additionally, bearing in mind that I'm yet to study capacitors in any level of detail, does the voltage not correspond to a maximum input voltage that the device can handle without being damaged, destroyed, or at least cease to function?

The manufacturer guarantees that the maximum percentage difference
below/above the catalogue value will be –10% / +50%.
 
Are you reading "percentage difference" as "percentage potential difference" or something similar?
 
Martinet said:
Are you reading "percentage difference" as "percentage potential difference" or something similar?

yes...oops
thanks
 

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