Day 5 3/8 Nodal Analysis with Voltage Source

 Today, we learn about nodal analysis with voltage source.

At the beginning of the class, after professor explained, we were given an exerices.

 use nodal analysis to calculate the voltage Vx.

In this photo, we need to use nodal analysis to calculate the voltage Vx. Because we did wrong on our whiteboard, so we use the whiteborad of professor. There are 3 equations and 3 unknows and we finally find the Vx=30V.

Next, we did the lab: Nodal Analysis

Purpose:The purpose of the lab is to use nodal analysis to calculate the voltage V1 and V2. Then, compare the theoretical value of voltage to the actual value. 

Pre- lab question:

Here is our group work.

In this photo, we use nodals to set up equations and find V2=4.4V and V1=2.36V.

Then professor asked us to change the values of resistor and we fing that if the three resistors changed at the same range, the answer doesn't change. But if the resistors changes at the different range, the answer would be differnet. 

Then we began to set up the lab.

In this photo, we measure the values of three resistors.

In this photo, itis the set up of  experiment. We just build it like the circuit in pre-lab. And we mearusre the values of V1 =2.464 and V2=4.40V

In this photo, we wrote down the values we have. And find the % difference of V1=4.36% AND % difference OF V2=0.

We get our % difference not that much. This is not exactly 100% same as theoretical value because the resistor we are using are a little bit off. Overall,  the results are reasonable.

 Next we learn something new about Mesh Analysis.

In this photo, we set up two circles and write two equations to find i1=1 ohms and i2= -2 ohms. 

In this photo, we use the everycircuit to check our answer. And we find  it is correct.

Next, we review what we learned in Physics 4B class, which is how to find the ohms of a resistor. 

  In this photo, the color is red black orange and the resistor is 20 kohms

Then in this photo, we find 4 different resistors' values of 3 colors

In this photo, we find resistors of 4 colors.

Summary:

In today’s lab, we learn how to do nodal analysis. It simplifies the way we solve the equations. We also learn how to do mesh analysis. After that we reviewed how to find the values of resistor by colors.