Problem 4(i): (a) A 3.0 µF and 4.0 µF capacitors are connected in series, and th

Question

Problem 4(i): (a) A 3.0 µF and 4.0 µF capacitors are connected in series, and this combination is connected in parallel with 2.0 µF capacitor, shown in fig. What is the net capacitance? and (b) If 26.0 V is applied across the whole network the calculate the voltage across each capacitor.

Problem 4(ii): The total resistance in the circuit shown is 15.0 k, and the battery’s emf is 24.0 V. If the time constant is measured to be 35.0 µs, calculate (a) the total capacitance of the circuit (b) the time it takes for the voltage across the resistor to reach 16.0V after the switch is closed.

Explanation / Answer

Here,

C1 = 3 uF

C2 = 4 uF

C3 = 2 uF

a)

for Ceq = (C1 series C2) parallel C3

Ceq = 3 * 4/(3 + 4) + 2

Ceq = 3.714 uF

the net capacitance is 3.714 uF

b)

for V =26 V

potential across 2 uF = 26 V ( as this is parallel connection)

potential across 4 uF = 26 * 3/(4 + 3)

potential across 4 uF = 11.15 V

potential across 3 uF = 26 - 11.15

potential across 3 uF = 14.85 V

part 4) ii)

as time constant = R * C

35 *10^-6 = 15 *10^3 * C

C = 2.33 *10^-9 F

total capacitance of the circuit is 2.33 *10^-9 F

b)

let the time taken is d

V = Vo * (1 - e^(-t/T))

16 = 24 * (1 - e^(-t/35))

solving for t

t = 38.5 us

the time taken is 38.5 us

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.