Day 11 - Tuesday, March 31, 2015 - Inverting Amplifier and Summing Amplifier

We started the day by analyzing the simplest Op Amp Circuit:

We

Then Mason asked what would the output look like when the input in an Op Amp is as shown on the left of the board. Then we drew an schematic.

Then we visualized what it would look like

Inverting Amplifier



Summing Amplifier

Our circuit looked like the following: 

Below is our collected data. 

We made a graph using excel that showed the relationship between the voltage that we were changing and the voltage that was coming out of the circuit:

Day 10 - Thursday, March 26, 2015 - Voltage Amplifier

Voltage Amplifier

This is a picture of the prelab that our classmates let us see.

Below is a picture of the prelab with the resistances that they are supposed to have and the resistances that we measured.

This is a picture of our circuit.

Day 9 - Tuesday, March 24, 2015 - Non-Ideal Power Sources and Maximum Power Sources

Non-Ideal Power Sources

Below is a picture of our pre-lab. We figured out the current running through our circuit and the power that we would see if the circuit elements were ideal. This is on the left of the picture. A more realistic calculation would include the resistance from within the battery. The formulation for this is found on the right side of the board.

In here, the power, voltage and current that are relevant to the 22 ohm resistor are calculated.

Below are our answers to the lab questions.

This is a picture of our circuit.

Maximum Power Sources

Below is  a picture of our prelab.

We set up our circuit and measured the voltage across the resistor.

And we calculated our percent error.

Day 8 - Thursday, March 19, 2015 - Thevenin's Theorem

Getting Started with EveryCircuit

Thevenin's Theorem

This is the picture of the circuit.

This is a picture of the circuit with the   on the left as the resistor and the   on the right as the   that we were measuring

Day 7 - Tuesday, March 17, 2015 - A BJT Curve Tracer

A BJT Curve Tracer

We took pictures and videos of our running signals:

First is the sinusoidal signal.

Second is the triangular signal.

Third is the square signal.

Our data was supposed to look like the graph on the picture.

But we got something that looked like the box on the lower right corner of the photo:

This is because the circuit seems to have reached saturation point.

In the end this is the signal we were able to obtain from our circuit.

These are the signals with the values that we were feeding into the circuit.

Day 6 - Thursday, March 12, 2015 - Mesh Analysis III

Today's lab is called:

Mesh Analysis III

Below is a picture of our circuit:

This is a picture of the Analog Discovery providing the required voltage to our circuit:

This is a measurement of the voltage across one of the resistors:

We worked our equations to find out the theoretical currents on our circuit:

Finally we measured the voltage and current across our resistor. 

Day 5 - Tuesday, March 10, 2015

Nodal Analysis

for the lab:
do some write up
schematic

Below are the resistances that we measured for our resistors. Their actual resistances can be seen in the picture above.

This is a picture of our circuit.

We did a calculation of our circuit.

expected values
experimental values
analysis on why we didn't get exactly what we predicted

Day 4 - Thursday - March 5, 2015

Today we had a fiesta and it was the following

Quiz 1 (Fiesta 1)

Then we had lab

Temperature Measurement System

Video

Day 3 - Tuesday - March 3, 2015 - Dusk-to-Dawn Light

Today we started the day with a fun conceptual check about the drop in potential on circuit elements. Prof. Mason grabbed a hot dog with some LEDs and hooked them up as part of a circuit as shown below and asked which LEDs would turn on if any.

Counting from the left, the first, fourth and fifth LEDs are positioned so that their leads are parallel with the hot dog and the current. The second and third LEDs have their leads perpendicular to the hot dog and current. Remembering that potential drop occurs as current goes through a circuit element, it may seem at first that all LEDs should light up. However, the orientation of their leads makes a decisive difference.
The LEDs that have their leads perpendicular to the current receive current with the same amount of potential on both of their leads, meaning that there is no potential difference across them; hence, no current will flow through them. Meanwhile the LEDs with their leads parallel to the hot dog will receive currents with different potential. This means that there is a potential difference across them and current will flow and they will light up.
However, since they are getting their energy from the hot dog, they will receive very little because the hot dog has a high resistivity. This also means that the hot dog will get very hot as shown in the video below.

Then we worked out a problem.

Dusk-to-Dawn Light

This is the data. 

Below is a video of our circuit working

Day 2 - Thursday - February 26, 2015 - Resistors and Ohms Laws - Voltage-Current Characteristics and Dependent Sources and MOSFETs

Today we started by analyzing the following circuit:

And asked us what happens to the light bulbs when the switch is turned on. My group answered that the top light bulb would bet brighter and the bottom bulb would remain the same. ThenMason set it up and showed us what actually happens.

Both light bulbs remained the same. In other words, they didn't get brighter or dimmer. The reason for this is that the battery adds 1 V at the top and takes 1 V after the current goes through the first bulb. So the total voltage at the top is 3 V and 2 V after the first light bulb which is a voltage drop of 1 V across the first light bulb. This means that the top light bulb has the same intensity. Then the second light bulb receives a 1 V and uses it. This happens when the switch is on and off.

Then we did two labs:

Resistors and Ohms Laws - Voltage-Current Characteristics

For this lab, we hooked up a 100 ohms resistor to the Analog Discovery, which provided the voltage) and made a closed circuit.

We chose several values for the voltage and measure the current running through it. Below is a chart of our data:

Then we analyzed it with Excel

 And got the following graph:

Our line had a perfect fit for our data. From the equation, G, which is equal to 1/R, is equal to 9.0714 1/ miliohms. This means that our R =  0.110 miliohms or 110 ohms.


Dependent Sources and MOSFETs

Below is a diagram of our circuit:




We hooked up a 100 ohm resistor in series with a MOSFET and our voltage source (Analog Discovery). A picture is shown below.

We need to find the threshold voltage. We did this by gradually applying more voltage until the DMM showed current flow. The recorded threshold voltage is :

Then we increased the voltage by increments of about 0.3 V up to 5 V. The data with tabulated values is provided below:

We analyzed our data with Excel and obtain the following curve:


The transistor seems to be behaving like a voltage-controlled current source (VCCS).

The estimated value of g is:

It was determined by