College physcs

posted by .

A capacitor in a single-loop RC circuit is charged to 64% of its final voltage in 1.5 s.
Find the time constant for the circuit.

Find the percentage of the circuit's final voltage after 3.9 s .
Vc/Vi= %

  • College physics -

    The voltage across the capacitor is
    Vi * [1 - e^-(t/RC)]
    in this type of circuit. Vi is the power supply voltage. RC is the time constant.

    The final voltage is Vi.
    When t = RC (the time constant), the voltage is
    Vc = Vi*[1 - e^-1] = 0.632 Vi

    When t = 1.5 s,
    0.64 Vi = Vs * [1 - e^(-t/RC)]
    e^(-t/RC)= 0.36
    t/RC = 1.02
    RC = 1.5/1.02 = 1.47 seconds
    That is the time constant.

    After 3.9 s

    Vc = Vi* [1 - e^(-3.9/1.47)]
    = 0.930 Vi

    Unless you show some work on future posts here, I will not be assisting you again. Perhaps someone else will.

    Vc = Vi* [1 - e^(-3.9/1.47)]
    = 0.930 Vi

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physics

    which one of the following statements concerning an ac circuit is true?
  2. Physics!! Help!!!!!

    The time dependence of voltage across a discharging capacitor is given by the exponential decay. The voltage on the capacitor at time t= 0 sec is 24 volt. If a 220 +/- 22uF capacitor and 1 Mega ohm (5% tolerance) resistor are used …
  3. physics, help with circuits please!

    Can the voltage across any of the three components in the R-L-C series circuit ever be larger than the maximum voltage supplied by the AC source?
  4. Physics, help please!

    Can the voltage across any of the three components in the R-L-C series circuit ever be larger than the maximum voltage supplied by the AC source?
  5. Physics help please!

    Hi all. I posted earlier but I'm still stuck on part of this problem. I thought that statements 2 and 3 were correct below. But I got the problem wrong. Any help would be great! Can the voltage across any of the three components in …
  6. Physics circuit help please!

    Hi all. I posted earlier but I'm still stuck on part of this problem. I thought that statements 2 and 3 were correct below. But I got the problem wrong. Any help would be great! Can the voltage across any of the three components in …
  7. physics

    An RLC circuit has voltage supplied to it at a frequency of 13.0 kHz with a phase difference between the current and the voltage of magnitude 0.20 rad. If the circuit has a capacitance of 5.0 µF and an inductance of 0.050 H, find …
  8. physics

    In the circuit below, at time t = 0, the switch is closed, causing the capacitors to charge. The voltage across the battery is 12 V The circuit: flickr. com/photos/ 68751220@N03 /6848519773/ A)Calculate the time constant for the RC …
  9. Physics- Repost (Answer did not make sense)

    In the circuit below, at time t = 0, the switch is closed, causing the capacitors to charge. The voltage across the battery is 12 V The circuit: flickr. com/photos/ 68751220@N03 /6848519773/ A)Calculate the time constant for the RC …
  10. Physics 112

    A battery is connected in series with a R = 0.26 Ω resistor and an inductor, as shown in the figure below. The switch is closed at t = 0. The time constant of the circuit is τ = 0.10 s, and the maximum current in the circuit …

More Similar Questions