Capacitor Peak Current and Voltage in an AC Circuit

In summary, the peak current of a capacitor is 240 μA at a peak voltage of 2.7 V and frequency of 250 kHz. To find the capacitance, the equation Xc=1/wC can be used. Solving for Xc, we get 11250. To find the peak current at 500 kHz, the frequency needs to be converted to radians/sec by dividing by 2pi. The correct capacitance is 3.56x10^-10 F.
  • #1
ReidMerrill
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2

Homework Statement


A capacitor has a peak current of 240 μA when the peak voltage at 250 kHz is 2.7 V .
Part A
What is the capacitance?

Part B
If the peak voltage is held constant, what is the peak current at 500 kHz

Homework Equations


Xc=1/wC
Vc=IcXc

The Attempt at a Solution


I rearranged equation 2 to solve for Xc = 2.7V/0.000240A = 11250
I then rearranged equation to to solve for C =1/wXc = 3.56x10-4

This is not correct. Why is this not correct and what is the proper way to go about solving it?
Thank you.

Correction: I re-did the second calculation and got 3.56x10-10F by properly converting kHz to Hz but it's still wrong.
 
Last edited:
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  • #2
Hi ReidMerrill.
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Did you convert kHz to radians/sec?
 
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  • #3
NascentOxygen said:
Hi ReidMerrill.
aerobanner.gif


Did you convert kHz to radians/sec?
Oh you know what I did not. I wasn't aware I needed to. My professor did not explain this well at all.
I would just divide the frequency by 2pi, correct?EDIT: That worked. Thank you!
 
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What is a capacitor?

A capacitor is an electronic component that can store and release electrical energy. It consists of two conductive plates separated by an insulating material called a dielectric.

How does a capacitor work in an AC circuit?

In an AC circuit, a capacitor alternately stores and releases electrical energy as the direction of the current changes. This allows the capacitor to smooth out voltage fluctuations and filter out unwanted frequencies.

What is the role of a capacitor in an AC circuit?

The main role of a capacitor in an AC circuit is to store and release electrical energy. It can also be used to block DC current and allow only AC current to pass through.

How does the capacitance of a capacitor affect an AC circuit?

The capacitance of a capacitor determines the amount of charge it can store. In an AC circuit, a higher capacitance will allow the capacitor to store more energy and have a greater effect on the circuit's voltage and current.

Can a capacitor in an AC circuit affect power factor?

Yes, a capacitor in an AC circuit can affect power factor. Capacitors can be used to correct power factor by storing and releasing reactive power, which can help balance out the reactive power consumed by inductive loads in the circuit.

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