# Cube Capacitor Problem

#### CrawlingInCollege

Joined Mar 31, 2021
1
Got anxious about it and I don't know how to start solving this. Sorry for the bad drawing.

#### ericgibbs

Joined Jan 29, 2010
18,623
hi CinC,
Welcome to AAC.
E

#### Ian0

Joined Aug 7, 2020
9,438
Symmetry is the key.

#### MrAl

Joined Jun 17, 2014
11,250
Got anxious about it and I don't know how to start solving this. Sorry for the bad drawing.View attachment 234070
Hey this is interesting. I assume that all the capacitors are of equal value?
With the right values for each capacitor and oriented correctly this can be taken as an elemental electrostatic space element in three dimensions.

But there are different ways to approach the problem at hand, so maybe you should mention what you have learned so far and provide your best attempt to solve it so we know.

#### Ian0

Joined Aug 7, 2020
9,438
Try it with resistors - you can actually build it and measure it with a meter to prove whether you have got it right.

#### atferrari

Joined Jan 6, 2004
4,747
I solved a resistor cube using delta wye conversions.

After that it was implemented in a protoboard and finally in LTSpice.

#### RBR1317

Joined Nov 13, 2010
712
You could use nodal analysis; there are only six nodes. It should be simple enough; all voltage drops across capacitor reactance instead of resistance (pick a frequency - any frequency).

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#### Ian0

Joined Aug 7, 2020
9,438
If you draw the cube, the connections are at A and D. A connects to three identical points B via an impedance, and D connects to three identical points C via an impedance.
Each B joins to two Cs via an impedance. Each C joins to two Bs. All impedances are equal.
So if you joined all three Bs together with a piece of wire, then no current would flow in the wire, as the voltage across its ends would be zero
Same for C.
Now does it look easier?