Design a combination of Capacitors

[Shreya]

Homework Statement

It is required to construct a 10mF capacitor which can be connected to a 200V Battery. Capacitors of Capacitance 10mF are available but they can withstand only 50V. Design a combination which can yield the desired result.

Relevant Equations

C=Q/V

My attempt was this:

The textbook answer was:

Is my approach wrong?

 

[jbriggs444]

Is my approach wrong?

Both approaches are valid.

If one wanted to choose between those two approaches (or other possible approaches), then it would be interesting to consider the effect of a failure (fail open or fail closed) of one of the components.

 

[Shreya]

interesting to consider the effect of a failure (fail open or fail closed) of one of the components.

On failure of components, the textbook answer would be preferred,right?

 

[jbriggs444]

On failure of components, the textbook answer would be preferred,right?

Not necessarily. It depends on what failure type is most prevalent.

A series array of capacitors in parallel will not change its capacitance much if one element fails open.
A parallel array of capacitors in series will not change its capacitance much if one element fails closed.

But then one should also be concerned with the possibility of cascading failure. I do not build such things for a living, so I cannot offer an opinion on which approach is "best" in real life.

Edit: a quick trip to Google says that ceramic capacitors tend to fail closed (short circuit) on overload.

Cascading failure yields a short circuit either way.