Figure 2118 6HF 90V A system of capacitors is connected acro

Figure 21-18 6HF 90V A system of capacitors is connected across a 90 VDC voltage source as shown in Figure 21-18. What is the equivalent capacitance of this system? A) 3.3 uF B) 15 uF D) 3.6 uF E) None of the other answers is correct

Solution

2 uF and 4 uF are in series.

so equivalent of these is C\'.

then 1/C\' = 1/2 + 1/4

C\' = 1.33 uF

3 uF and 6uF are also in series.

equivalent of these is C\" then

1/C\" = 1/3 + 1/6

C\" = 2 uF

now C\' and C\" are in parallel.

Ceq = C\' + C\" = 1.33 + 2 = 3.3 uF

Ans(A)