Matlab

Solving Simultaneous Equation

Dependent Source and MOSFETs

In the experiment we setup VCCS and tested the results.

Lab:

We setup the circuit in the bread board and connected the analog box.

Using wavegen we supplied voltage from 0 to 5V, and we measured the current.

We repeated the step 9 more times, and plotted a graph of Voltage vs Current.

Looking at the chart the threshold voltage of the MOSFET is around 36.1V. The MOSFET is behaving like a dependent source. Since as we change the value of the voltage the current also changes. Using the plot we created a line of fit to get the slope the line which is the value of  g.

g = 10.124

Mesh Analyis 2

In this experiment we predicted the values for voltage and current using mesh analysis. 

Prelab:
Using mesh analysis we calculated the value of current and voltage in the circuit.

i1 = 5.56E-05A

i2 = -0.00032A

i3 = -0.00106A

I1= -0.00032A

i = i2 - i3

i = -0.00032A - -0.00106A       

i = 7.4E-4A

V1 = iR

V1 = 7.4E-4A(6800ohms)

V1 = 5.032V

Lab:
We first measured the resistance of the different resistor we are using.

Circuit setup

Current and Voltage value measure.

Percent error between measured and expected values of V1 and I1. The voltage values are acceptable but the value for current has a large percent error.

Temperature Measurement System

This experiment used a thermistor that change resistance with the temperature.

Prelab:
We first calculated the values of R for the temperature between 25°C and 37°C,and voltage out(Vout) value increases by a minimum of 0.5V. The value calculated for R is between 5727ohms to 9000ohms. The resistor that we have in the lab that is between the calculated value is 8200ohms.

From the graph Temperature vs Resistance:

11000ohms @ 25°C

7000ohms @ 37°C

Lab:

First check the resistance value of the given resistor. R = 7.98Kohms

We also check if the thermistor is working by changing its temperature from room temperature to normal body temperature. The value of thermistor's resistance is inversely proportional to temperature.

The bread board setup

Then we measured the voltage in room temperature to normal body temperature.

Intial Voltage - 2.18V

Final Voltage - 2.74V

Output Voltage increase - 0.58V

The Output voltage is close to the desire value of 0.5V over the temperature range of 25 to 37 degree C.

Percent Error 

Video Clip:

Dusk- to- Dawn Light

This experiment is using photocell (a resistor that varies its value depending on the amount of light) as a sensor to light the LED.

Prelab:

We calculated the value of the voltage for photocell resistance of 5K and 20K.

Lab:

First we measure the resistance of the photocell in different light source to check if it is working.

We also check voltage of the analog box. We set the value for the on the wave gen on 5V DC.

The we construct the circuit on the bread board. Connecting the circuit the scope instrument on the analog box, data were collected.

Video Clip

Resistor and Ohms Law

 

 In this lab we measured combination of voltage and current to create a graph of voltage vs current and see the relation between the two.

First we used a 100 ohms resistor and measured its actual resistance (99.7 ohms), then the resistor is connected it to a voltage supply of 3V to 12V. We recorded the data and plot it in a graph

Solderless Breadboards, Open- circuits and Short- circuits

In this experiment, we measure the resistance of different setup using DMM as ohmmeter. The resistance measured shows whether the circuit is open or closed.

In this setup we have the ohmmeter connected to the two holes that is in the same row on the breaf board. The measured resistance is 0.26ohm and it is a closed circuit.

We checked the resistance value of two holes that are in the same row but in opposite side of the bread board. The value measured is 1 and it is an open circuit.

The ohmmeter is connected to the bread board in two hole that are not on the same row. The measured resistance is 1 which shows that this is an open circuit.

This setup has a ohmmeter on different row and side; we used a jumper cable to connect the two row. The measured resistance value is 0.19 and it is a closed circuit.