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Question
Convince yourself that parts (a), (b) and (c) figure are identical. Find the capacitance between the points A and B of the assembly.
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Solution
Parts (a), (b) and (c) are identical, as all of them form a bridge circuit. In that circuit, capacitors of 1 µF and 2 µF are connected to terminal A and the 5 µF capacitor and capacitors of 3 µF and 6 µF are connected to terminal B and the 5 µF capacitor.
For the given situation, it can be observed that the bridge is in balance; thus, no current will flow through the 5 µF capacitor.
So to simplify the circuit, 5 µF capacitor can be removed from the circuit.
Now, 1 µF and 3 µF capacitors are in series.
And 2 µF and 6 µF capacitors are also in series combination.
These two combination are in parallel with each other.
The equivalent capacitance can be calculated as :-
`C_(eq) = (1 xx 3)/(1+3) + (2 xx 6)/(2+6)`
`= 3/4 + 12/8 = 9/4 "uF" = 2.25 "uF"`
`therefore = C_(eq) = 2.25 "uF"`
Thus , parts (a) , (b) and (c) are identical.
And,
`C_(eq) = 2.25 "uF"`
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