# Finding voltage and phase

#### gbox

Joined Dec 29, 2015
42
Find V_ab and |V_ab| and the phase of V_ab.

I thought about using Thevenin, but than I thought that the elements above AB are the same as under AB.

Or I can just say that $$V_AB=V_source-Z_R-( V_source-Z_C)$$?
How should I approach this?

Last edited:

#### WBahn

Joined Mar 31, 2012
29,519
Do you know about complex impedance?

#### gbox

Joined Dec 29, 2015
42
Do you know about complex impedance?
I know that
Code:
[plain]$$V_source=V_in*e^{\omega t} Z_R=R and Z_C=\frac{1}{\omega c i}$$[/plain]

#### gbox

Joined Dec 29, 2015
42
Here is the attempt

#### WBahn

Joined Mar 31, 2012
29,519
I know that
Code:
[plain]$$V_source=V_in*e^{\omega t} Z_R=R and Z_C=\frac{1}{\omega c i}$$[/plain]
Okay, so if you were asked merely to find the voltage at Node A, could you do it?

If you were asked to merely find the voltage at Node B, could you do it?

If so, recognize that V_ab is, by definition, the voltage at Node A minus the voltage at Node B.

#### gbox

Joined Dec 29, 2015
42
Okay, so if you were asked merely to find the voltage at Node A, could you do it?

If you were asked to merely find the voltage at Node B, could you do it?

If so, recognize that V_ab is, by definition, the voltage at Node A minus the voltage at Node B.
I have used voltage divider is it right?

#### WBahn

Joined Mar 31, 2012
29,519
Your image capture doesn't have enough contrast for my tired old eyes to read easily, but it appears you are starting out on the right path.

#### anhnha

Joined Apr 19, 2012
905
I have used voltage divider is it right?
Your approach using voltage divider is right but you need to review the formula to calculate voltage across each element of a voltage divider.