Wednesday, February 15, 2017

Blog 6 group 1

1. You will use the OPAMP in “open-loop” configuration in this part, where input signals will be applied directly to the pins 2 and 3.

a. Apply 0 V to the inverting input. Sweep the non-inverting input (Vin) from -5 V to 5 V with 1 V steps. Take more steps around 0 V (both positive and negative). Create a table for Vin and Vout. Plot the data (Vout vs Vin). Discuss your results. What would be the ideal plot?
Vin Vout
-5 -3.97
-4 -3.97
-3 -3.97
-2 -3.97
-1 -3.97
0 0
1 4.49
2 4.49
3 4.49
4 4.49
5 4.49
Table 1: Vin vs Vout for non-inverting
Graph 1: Shows Vin vs Vout on the non-inverting

Our values received make sense because the amplifier has a higher gain but a restriction on voltage.  So the values are going to increase close to the 5V right away because the gain amplifies it.

b. Apply 0 V to the non-inverting input. Sweep the inverting input (Vin) from -5 V to 5 V with 1 V steps. Take more steps around 0 V (both positive and negative). Create a table for Vin and Vout. Plot the data (Vout vs Vin). Discuss your results. What would be the ideal plot?

Vin Vout
-5 4.49
-4 4.49
-3 4.49
-2 4.49
-1 4.49
0 0
1 -3.98
2 -3.98
3 -3.98
4 -3.98
5 -3.98
Table 2: Shows Vout vs Vin for the inverting
Graph 2: Shows Vout vs Vin on the inverting

Our values received make sense because the amplifier has a higher gain but a restriction on voltage.  So the values are going to increase close to the 5V right away because the gain amplifies it. But since this one is inverting, the negative input gives a positive output and vice versa.

2. Create a non-inverting amplifier. (R2 = 2 kΩ, R1 = 1 kΩ). Sweep Vin from -5 V to 5 V with 1 V steps. Create a table for Vin and Vout. Plot the measured and calculated data together.


Vin Vout
-5 -4.24
-4 -4.24
-3 -4.24
-2 -4.24
-1 -2.73
-0.5 -1.56
0 0
0.5 1.56
1 2.73
2 4.24
3 4.24
4 4.24
5 4.24
Table 3: Shows Vin vs Vout with the resistors

Graph 3: Shows Vin vs Vout with the resistors

3. Create an inverting amplifier. (Rf = 2 kΩ, Rin = 1 kΩ). Sweep Vin from -5 V to 5 V with 1 V steps. Create a table for Vin and Vout. Plot the measured and calculated data together.
Vin Vout
-5 4.2
-4 4.2
-3 4.21
-2 4.2
-1 2.152
-0.5 1.061
0 0
0.5 -1.031
1 -2.2
2 -3.8
3 -3.8
4 -3.8
5 -3.8
Table 4: Shows Vin vs Vout with the resistors
Graph 4: Shows Vin vs Vout with the resistors

4. Explain how an OPAMP works. How come is the gain of the OPAMP in the open loop configuration too high but inverting/non-inverting amplifier configurations provide such a small gain?
OPAMP works by not allowing any resistance to divide the gain.  It has two inputs of opposite polarity and has a single output with a very high gain.

RELAY:
1. Connect your DC power supply to pin 2 and ground pin 5. Set your power supply to 0V. Switch your multimeter to measure the resistance mode; use your multimeter to measure the resistance between pin 4 and pin 1. Do the same measurement between pin 3 and pin 1. Explain your findings (EXPLAIN).
When measuring the resistance between the pins, 4 and 1 received a value of 6.5 ohms, and pins 3 and 1 overloaded the circuit.  Since Vout on pin 4 is based off of the Vin being less then the threshold, since there is no voltage being inputted, Vin will receive a value on pin 4.

2. Now sweep your DC power supply from 0V to 8V and back to 0V. What do you observe at the multimeter (resistance measurements similar to #1)? Did you hear a clicking sound? How many times? What is the “threshold voltage values” that cause the “switching?” (EXPLAIN with a VIDEO).
Video 1: Shows when the relay threshold takes place
When increasing the voltage, you hear a single clicking noise from the relay around 5 Volts.  When turning the voltage back you hear another clicking noise around 2.5 Volts.  

3. How does the relay work? Apply a separate DC voltage of 5 V to pin 1. Check the voltage value of pin 3 and pin 4 (each with respect to ground) while switching the relay (EXPLAIN with a VIDEO).
Video 2: Shows when the relay switches and how it works
A relay works kind of like a transistor, you have to reach a certain voltage before anything changes.  Our threshold changes at 5V and 2.5V.  So pin 3 and 4 will swap values once the relay switches.

LED+RELAY:
Video 3: Shows how the relay works with a diode
The diode activated once the relay is switched when you hit 5V, and is switched off once you drop back below the lower threshold of 2.5V.

OPERATIONAL AMPLIFIER:

1. Connect the power supplies to the op-amp (+10V and 0V). Show the operation of LM 124 operational amplifier in DC mode with a non-inverting amplifier configuration. Choose any opamp in the IC. Method: Use several R1 and R2 configurations and change your input voltage (voltages between 0 and 10V) and record your output voltage. (EXPLAIN with a TABLE)
Input Output V (R1=2K R2=1K Output V (R1=1K R2=1K Output V (R1=120 R2=1K
1 1.5 2 8
2 3 3.78 8.46
3 4.5 5.9 8.58
4 5.8 7.8 8.58
5 8 8.58 8.58
6 8.58 8.58 8.58
7 8.58 8.58 8.58
8 8.58 8.58 8.58
9 8.58 8.58 8.58
10 8.58 8.58 8.58



















16 comments:

  1. I noticed in all of your OPAMP outputs, the value never reached the full value of the input. Our experiments came up with the same results, there must be some loss in the OPAMP circuit.

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  2. In number 4 you didn't explain why the open OPAMP has a higher gain than non-inverting or inverting OPAMPs. I suggest you fix that so you don't get marked down.

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  3. for questions #2 and #3 i realize that you missed the calculated values for the Vout , the rest of the questions seems perfect for me.

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  4. Your data are very close to ours. For Question number 2 and 3, I think we have to make a third column for Vout calculated data as I got form the question and thats what we did in our blog, but I am not sure we might be wrong. For the last part "Operational Amplifier". You did answer only the first question. I don't see questions 2 and 3. Everything else is well explained and clear.
    Well done

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  5. For Question 1 (second one), Our group had the same out come of one being overloaded and the other gives off a value, however our two readings are quite different where yours was 6.5 and our value was 1.3 ohms, not sure if we had a different voltage source value or what to have this difference

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  6. Some text for the graphs and tables other then captions would be good. For numbers 1 and 2 your missing calculated values on your table and graphs. your tables are very nice though. how did you do them?

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  7. The blog is organized and easy to read. Questions 2 and 3 measurements are close to our results with slight difference,however, you should include the calculated output voltage for Q2 and 3 and then plot it in the graph to get two lines. Also, I think you could add some more explanation to question 4. The rest looks good.

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  8. For question 1, my group thought there would be different values for the ideal opamp output between the values of -1 and 1 volt for the input because of the theoretically high gain of this setup. How do you think your graph of your data compares to the theory? Would the slope of the interval between -1 and 1 differ from your plot?

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  9. Our values seem pretty close, but you do not include calculated values for questions 2 and 3. The rest of your blog look good except for the parts not done.

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  10. Nice use of the breadboard in the LED and Relay circuit video, very easy to see which wires go where! Your tables also correlate to our own for 1a and 1b, meaning that there is quite likely a bias in non-inverting and inverting op-amps to negative and positive outputs.

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  11. We seemed to have flip flopped values for number 1. Do you think that is an error on our part or yours? I believe we may have gotten our graphs and tables mixed up. For most of the values, we had similar results. In general, our data matched up. Your relay videos were very well put together. They were easy to understand and showed the info accurately. You did a great job at keeping them short, but including all of the requirements.

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  12. Its difficult, but try to get the tables and plots next to each other (for readability). Don't forget your calculated tables and plots for #2, and #3. your values for the first couple of questions seem to match ours, If you do a R1=1k and R2=1k wouldn't that make your gain equivalent to 1? I haven't actually tested it out so im not sure. It doesn't seem like you finished your blog, there is a lot of missing items.

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  13. For your first 4 questions, you will want to include calculated values as well as measured values, and will want to describe what the ideal curve would be, whilst describing whether or not your curve is ideal.

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  14. I definitely like the colors you use in your blog, because blue and bold gray are easy to read together. Your data looks good, and I like that you included captions under your pics and videos. Nice work.

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  15. The values you guys got were pretty close to what we got. The colors in the graph definitely make it easier to visualize how Vout changes. You guys could've added the calculated value to show how it differs, but its not required. Good job

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  16. Your data was quite similar to ours, for number 2 however our Vout was a lot closer to what you'd expect it to be with the gain value we used. do you have any idea why this might be? also nice job with the graphs and tables, very clear and easy to read.

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