Nodal analysis/ Mesh Analysis

Today in class we learned about Nodal analysis and Mesh Analysis. Mesh Analysis are opposite from nodal analysis. In Mesh analysis we assigned loop and find i of that loop rather than finding V or i of each branch like we did in nodal analysis. 

We also learned about supernode where we have Voltage source given instead of current. 

Following are few examples we did in class for supernode analysis and mesh analysis.

Nodal Analysis LAB:

We analyzed built  and test following circuit containing multiple sources by using nodal analysis to predict the circuit behaviour. We compared our measured values with calculated values and also calculated our % error. 

Here are few pictures of circuit set up.

We got 4.37 V and 2.41 V measured value of v1 and v2. 

Final calcualtion of nodal analysis lab circuit with measured and calculated values.
Our % error was 0% for  V1 and 1.04% for V2. you may see the calculations below.

Uncertainity: in this lab our uncertainity was voltage fluctating in multimeter. We did not use exact capacitors. For example 22K resister was 21.72K when we measured it with multimeter.
Post LAB: we learned to do nodal analysis through this lab and found small % error  between calculated and measured values due to decimal lost and not using exact values of resisters.

Mesh Analysis Problem that we did in class. below was our solution

Down to dusk light lab

We did hotdog experiment where we attached a hotdog to a line cord and apply a 120 V potentional across it. The hotdog slowly cooked. Then we inserted LED into the hotdog both parallel and perpendicular to the hotdog axes. The LEDs perpendicalr to the hotdog did not light and only the parallel LED light.

Following are few Series  and parallel circuit problem we did in class using KVL and KCL

Dusk to Dawn LAB: In this lab we created a light sensitive lighting system using BJT. Below are some images of our set up and also video of light turning off and on. 

We use KVL around the outer loop of the circuit to determine the voltage Vb for photocell resistance of 5K and 20 K. Below are images of our results. 

Following is an image of measured values of Vb for photocell resistances of 5K and 20 K and calculated values.

Quiz/temp measurement lab

We took group quiz and following wAs our answer . we use KCL and KVL to write a system of equations that allowed us to find the voltage across R1 as a function of I₁, I₂, R₁, R₂ and R₃.

 

Temperature Measurement system lab:  We created an electrical circuit which uses this resistance change to output a voltage which indicates the temperature of the thermistor. The system will use a thermistor to detect temperature changes. A thermistor is a device whose electrical resistance changes as a function of the temperature of the thermistor.

that the relationship between temperature and resistance is not linear

Our design criteria are as follows: Design a circuit like that shown, containing a thermistor as one of the resistances, which satisfies the following specifications:

1.      +5V input voltage to the system

2.      Output voltage varies by a minimum of 0.5V over a temperature range of 25^°C to 37^°C.

3.      Output voltage must increase as temperature increases

Following table of measured and calculated values with % error differance.

Following is a video of 12K ohm Resister used and voltage increase was .50 V. 

we used almost 4 other resisters. you can see our % error calculated above on white board. 

Uncertainity: we could have used better source of equipment for accurate results. the resisters didn't measured to be exact values. 

FreeMat LAB Introduction

The most common use of the plot command probably involves the vector-matrix paired case. Here, we generate a simple cosine, and plot it using a red line, with no symbols, which resulted in above graph. 

I plotted multiple sinusoids (at different frequencies). First, I constructed a matrix, in which each column corresponds to a different sinusoid, and then plot them all at once

Here's an example of Matrix on freemat

Dependent sources and MOSFET & Resisters an Ohm's law LAB

Resisters and Ohms Law voltage current characteristic lab:  In this lab we measured several combinations of voltage and current for a resistor and plot the resulting voltage-current characteristic curve measured for the resistor as showen in the below graph and data table. 

We compared two parallel lines on Voltage vs I graph. both lines says that at zero current their voltage is different.

In MOSFET lab a  simple voltage controlled current source is constructed and tested. we built and tested a circuit which acts as a Voltage Controlled Current Source

Graph of the voltage vs current and table is showen in below & above picture. Graph is just a straigh line.

Solderless Breadboards, Open-Circuits and Short-circuits LAB

Using DMM as an ohmmeter we me measured resistance between two holes from node a and node b.. we measured infinate resistance and it was open circuit.

Using DMM as an ohmmeter we me measured resistance between two holes from node a.. we measured 0.6 resistance and it was close circuit.

 Using DMM as an ohmmeter we me measured resistance between two holes from node a and node c. we measured infinate resistance and it was open circuit.

 Using DMM as an ohmmeter we me measured resistance between two holes from node a and node b.. we measured 0.5 resistance and it was close circuit.

Above are our written answers to questions which shows resistance measured with different nodes and characteristic of circuit.

Following are few images of DC Circuit problems done in class