Monday, February 13, 2017

Week Six

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(V)
Vout(V)
5
4.48
4
4.48
3
4.48
2
4.48
1
4.48
0
0
-1
-3.88
-2
-3.88
-3
-3.88
-4
-3.88
-5
-3.88
Table 1:The data (Vout vs Vin) NON-inverting
Graph1:  (Vout vs Vin) NON-inverting

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(V)
Vout(V)
-5
4.48
-4
4.48
-3
4.48
-2
4.48
-1
4.48
0
0
1
-3.88
2
-3.88
3
-3.88
4
-3.88
5
-3.88
Table 2: The data (Vout vs Vin) inverting
Graph2:  (Vout vs Vin) inverting

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(V)
Vout(v)
Measured
Vout(V)
Calculated
5
4.23
5
4
4.23
5
3
4.23
5
2
4.23
5
1.5
4.23
5
1
3.03
3
.5
1.35
1.2
.25
0.8
1
0
0
0
-.25
-0.8
-1
-.5
-1.61
-1.2
-1
-3.2
-3
-1.5
-3.77
-5
-2
-3.77
-5
-3
-3.77
-5
-4
-3.77
-5
-5
-3.77
-5
Table3:The data (Vout vs Vin) NON-inverting
Graph3: (Vout vs Vin) NON-inverting

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(V)
Vout(v)
Measured
Vout(V)
Calculated
5
-3.7
-5
4
-3.7
-5
3
-3.7
-5
2
-3.7
-4
1.5
-3.06
-2.5
1
-1.99
-2
.5
-0.99
-1.2
.25
-0.51
-0.6
0
0
0
-.25
0.5
0.5
-.5
0.98
1
-1
2.16
2
-1.5
3.01
3
-2
4.06
5
-3
4.16
5
-4
4.16
5
-5
4.16
5
Table4:The data (Vout vs Vin) inverting
Graph4: (Vout vs Vin) inverting

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?
 An OpAmp takes an input signal and amplifies it, providing a larger output signal. If the input signal is applied to the non-inverting input, then the output will have the same sign as the input. If the input is applied to the inverting input, then the output will have the opposite sign of the input. An OpAmp requires a source voltage in order to work and the output voltage cannot exceed the value of the source voltage.
     The gain of the OpAmp is determined by a ratio of the resistors used in an inverting/non-inverting amplifier configuration. This gain is what determines the factor by which the input voltage is multiplied to generate the amplified output voltage. Because an open loop configuration does not use any resistors to limit the effect of the amplifier, the gain is very high and the minimum and maximum output voltages are reached very quickly.







schematic view is the bottom view!
 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).
4-1 - 1.2 ohms
3-1 is not reading anything

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).



The voltage clicks when you approach 6 V, and it clicks when you are going back down and are approaching about 2.5 V.  It was like this for both pins.  For pins 1-3, it starts off with a 0 Ohm measurement.  Once it clicks after 6 volts, you can measure the resistance for pins 1-3, and it is the exact opposite for 1-4.  For 1-4, you can measure the resistance only before it clicks, and after it comes back from the second click. 



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).




For pin 3, at 0 Volts we have around 100 mV.  When approaching 6 volts, The voltage reading actually goes to a negative voltage and once clicks, it stays at 5 Volts.  The same is when sweeping back down, when it clicks the 5 Volts turns into a negative mV value and when it hits 0 volts it hovers around 100 mV.  For pin 4, it is the exact opposite.  At 0 Volts on the sweep, the voltage reading is 5 Volts.  When it clicks at 6 Volts, the voltage changes to a negative small mV value, and it stays that way until it clicks again on the sweep down and stays at 5 Volts.  




LED + Relay
1. Connect positive end of the LED diode to the pin 3 of the relay and negative end to a 100 ohm resistor. Ground the other end of the resistor. Negative end of the diode will be the shorter wire.



2. Apply 3 V to pin 1



3. Turn LED on/off by switching the relay. Explain your results in the video. Draw the circuit schematic (VIDEO)



We have 3 Volts going to pin 1, and are sweeping the voltage at pin #2.  Once pin #2 hits 6 volts, the relay is turned on and so is the LED light.  Once the voltage is sweeping down to 2 Volts, the Relay clicks and and the light is turned off.  



Operational Amplifier (data sheet under Bb/week 6)

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)
R1=2kohms, R2=12kohms  
Vin(V)
Vout(V)
0
0.5
1
7.89
2
9
3
9
4
9
5
9
6
9
7
9
8
9
9
9
10
9
R1=1kohms, R2=2kohms  
Vin(V)
Vout(V)
0
0.23
1
.89
2
2.5
3
9.37
4
9.37
5
9.37
6
9.37
7
9.37
8
9.37
9
9.37
10
9.37
R1=12kohms, R2=1kohms
Vin(V)
Vout(V)
0
0.8
1
1.2
2
2.4
3
3.1
4
4.2
5
5.3
6
6.4
7
7.8
8
8.5
9
8.8
10
8.9


3. Design a system where LED light turns on when you heat up the temperature sensor. (CIRCUIT schematic and explanation in a VIDEO)



33 comments:

  1. Your resistor measurement on the 2nd #1 involving pin 3 and 1 on the relay should be reading "OL". I think this means the resistance is too high to read and the circuit can be considered open, I was confused on that reading at first on our experiment as well.

    ReplyDelete
    Replies
    1. actually we got all the resistors values we didn't get error for that
      thanks for your comment

      Delete
  2. Our Group got very similar results for the inverting and non-inverting OPAMPs. The variation between our data and yours is most likely from the sensitivity of the knob. I do not see any issue with your blog. Keep up the good work.

    ReplyDelete
  3. Question number 1a and 1b, we did different measurement, but we both come up with the same results and graphs. For question number 2 and 3 there is a difference between our graphs. I couldn't see why, I don't know if you did see our blog or not. For question 4, I don't see any answer, I guess you haven't done it yet. Every thing else is clear and organized.

    Well done.

    ReplyDelete
    Replies
    1. actually, i saw your blog and i found that your graphs are different i think u might made an error doing that
      thanks for your comment

      Delete
  4. For Question 3, (Relay) our group only managed to get one readable voltage for one of the pins when one of the clicks went off, Im curious to how you guys managed to get another reading.

    ReplyDelete
    Replies
    1. i think it clicks at 6 volt and the second time whenu you go back to 2 volts
      thanks for your comment

      Delete
  5. I tried to compare our measurements and calculations which I found them very similar to your, than I think both of us have right experiment.
    Good job

    ReplyDelete
  6. your graphs are very nice an easy to read and understand. Your number 1 for the relay part could really use some more text explanation all you have is some numbers dashes and values.

    ReplyDelete
    Replies
    1. yes i realize that we should write more info about that
      thanks for your comment

      Delete
  7. your videos needs captions. Also, your graphs for Q2 and Q3 are similar to our graphs as well as our measurement. You also could add some explanation to the table's questions, this will make the table and the graph easy to understand. Other than that, good job

    ReplyDelete
  8. what is happening in the Relay to cause the click, and what is the meaning of the OL reading on the multimeter? On a similar note, what causes the LED to turn on in the LED Relay circuit?

    ReplyDelete
    Replies
    1. actually we got problem to figure out the answer for these questions
      thanks for your comment

      Delete
  9. Make sure you caption all your tables and videos. We got similar values in our data collected. You do a great job explaining in question 4. Other than that the blog is going good make sure to finish it up before class Monday.

    ReplyDelete
  10. Very thorough with your tables! I also like the superposition of the measured and calculated outputs. Very quiet in your videos though, at least for the amount of background noise going on.

    ReplyDelete
  11. We must have switched our tables for number 1 because we have opposite signs as your outputs. Why do you think the calculated is greater than the measured? We had very similar results for number 3. Your video for number 2 was a little confusing. Did you ever get it to work? Your descriptions on your videos were very helpful in understanding what the videos were about. Don’t forget to include your circuit diagram, but other than that it looks good.

    ReplyDelete
  12. If you can try some nicer crops, it takes a second longer, can also reduce amount of space pictures take up on screen. Make sure to include data points so that we can read your plots with your tables. Plots need Axis-titles, good job on including your calculated data with your measured for #2, and #3. It seemed like we had the same data. Explain what your doing and how the circuit is operating in your videos.

    ReplyDelete
  13. It may be a better idea to add more explanation to the figures on the first four problems. As well, include calculated data.

    ReplyDelete
    Replies
    1. we already include the calculated values for the first 3 questions
      thanks for your comment

      Delete
  14. It'd be nice if you would elaborate on why 4-1 is 1.2 ohms and 3-1 no read. Other than that your blog is definitely good.

    ReplyDelete
  15. Your graphs are probably the best ones I've seen so far. I like how you guys thought outside the box and added a graph for calculated value as well. The data was pretty similar to what we got, and the videos are pretty clear.

    ReplyDelete
  16. very nice job this week. your answer for #4 was very thorough and did a very nice job answering the question. Our answer shared the same ideas. Also most of our data was very similar with the exception of the last question where your resistor values were different. Good job!

    ReplyDelete