- #1
AntiStrange
- 20
- 1
Homework Statement
Calculate the circuit's impedance Z between input and ground for an applied sinusoidal voltage with frequency f = 1000Hz, and express Z in the form [itex]re^{i\theta}[/itex]
There is a picture that goes with it, it's just a function generator (makes a sinusoidal AC voltage) connected in series with a 0.1μF capacitor, and a 1kΩ resistor.
I think I solved it, but I would just like it if someone could verify that I did it correctly as it is going into a lab report.
Homework Equations
i.[tex]Z = \sqrt{R^{2} + (X_{L} - X_{C})^{2}}[/tex]
where X_L is for a transistor (none exists in the circuit so it's zero) and X_C is for the capacitor
ii. [tex]X_{C} = \frac{1}{\omega C}[/tex]
iii.[tex]tan(\phi) = \frac{\omega L - 1/\omega C}{R}[/tex]
All equations extracted from "University Physics by Young & Freedman 11th edition
The Attempt at a Solution
From Eq i, I just plugged in 1kΩ for the resistor, and X_L is zero, and I found X_C from Eq ii (where C is the 0.1μF capacitor and ω is 2π*1000Hz).
This gave me a value for Z of 1879.6Ω.
Then, to find it in the form [itex]re^{i\theta}[/itex], more specifically it should be:
[tex]re^{i(\omega t + \phi)}[/tex]
I know everything but φ, so I used Eq iii.
Again, L was zero so the first term in the numerator canceled out, and I found φ to be:
- 1.010 (radians).
So my final answer is:
[tex]1879.6 e^{i(2000\pi t - 1.01)} \Omega[/tex]
Is that all correct?
thanks.