Question

What is the capacitance between points $\text{A}$ and $\text{B}$ for the given assembly?

• A. $2.5\mu \text{F}$
• B. $5\mu \text{F}$
• C. $1.25\mu \text{F}$
• D. $2.25\mu \text{F}$

Answer 1

The correct option is D $2.25\mu \text{F}$



Since, the $5\mu \text{F}$ capacitor is connected across terminals $\text{P}$ and $\text{Q}$, We can redraw this circuit as shown below:



Now, $\frac{C_1}{C_2}=\frac{C_3}{C_4}=\frac{1}{2}$

So, $V_P=V_Q$ & $5\mu \text{F}$ can be neglected.

The circuit can be further reduced as shown below,


$C_{eq}=\frac{9}{4}\mu \text{F}=2.25\mu \text{F}$

Why this Question? Note: Always try to redraw a complex circuit, so that it gets converted into simpler one. After redrawing, look for any wheatstone bridge or parallel and series combinations.