Week 6

Operational Amplifiers

Explanations of the pin numbers are below:

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?

In this experiment, we applied a voltage from -5V (lowest value) to 5V(highest value) in an open loop configuration. When we applied the smallest value, we got the maximum output and that because in an open loop configuration, there is no resistors to reduce the operational amplifier effect which means that the maximum value will be reached even if we apply a small value. Also, the OpAmp has a very large gain and because of that the output will be large but because we applied a voltage value between -5V and 5V, our outputs will not be larger than 5V. Our maximum value was -3.7V and 4.4V as it is shown in the table.

Table1.1: show the vin and Vout of inverting input

Graph1.1: shows operational amplifier-sweeping inverting input

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?

We applied a -5V and 5V to investing input and the output results were the same value  but they were opposite signs as it is shown in the table. The maximum values were the same as the non-inverting input with different sign, for the - input the maximum value was 4.4V and for the + input the maximum value was -3.7V which is the opposite.

Table1.2: show the vin and Vout of non- inverting input

Graph1.2: shows operational amplifier-sweeping inverting input

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.

graph2.1: Non inverting amplifier

Table2.1:shows the measured and calculated output of a Non-inverting amplifier

In this lab, we measured  and calculated the output of non-inverting amplifier. The results of the measured and calculated part are close to each one. First, we used two resistors R1=1k and R2=2k which means the gain is 3. that give us of an output 3 times bigger than the input but for the -5V to -3V, the maximum voltage can't be bigger than 5 V so we put 5 V for the calculated. The graph shows the two lines of the the measured and calculated results. 

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.

graph3.1: inverting amplifier 

Table3.1:souls the measured and calculated output of an inverting amplifier 

In the inverting amplifier, we calculated the gain of Rf=2k and Rin=1k which was -(Rf/Rin)=-2. and because the gain is negative the output value will be opposite to input value as it is seen in the table. For input of -5V and 5V we calculated the output value and it exceeds the input value for values except( -2,-1,2,1) V.

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?

The Operation amplifier increases the the amplitude of the input signal and then the output signal will be larger by the gain factor. The gain in an open loop configuration is too high because it doesn't have any resistors which means the minimum value of input can reach the maximum output easily. However,  for the inverting/non inverting amplifier configuration, they provide a small gain because the gain is the ratio between the two resistors which means there gain will depend on the value of the resistors and there output will be the the input multiplied by the gain factor.





EGR 393 Temperature Controlled LED System 
Tips:
1. If something is not working, check your connection first.
2. Check the pins carefully, LM35 is VERY easy to be burned if you connect the wrong pins.
3. Read the datasheet carefully.
4. Before starting to connect the circuit, try to sketch it on a paper first, make sure everything is clear.

Components:
1. TMP36 Temperature Sensor 2. Lm324 Operational Amplifier 3. OMRON G8QN Relay 4. LED

Procedure:

TMP36 Temperature Sensor: Pin layout – look up characteristics to calculate temperature from datasheet (under Bb/Week6).

Temperature Sensor: Put TMP36 temp sensor on breadboard.
* Connect the +VS to 5 volts and GND to ground.
* Using a voltage meter, measure the output voltage from the VOUT. Now put your finger (or cover the sensor with your palm) on the TMP36 temperature sensor for a while, observing how the output voltage changes. Check Fig. 6 in the data sheet (EXPLAIN).







Relay (Manual under Bb/Week6) 

Pin 1 – Input voltage (amount of voltage sent to pins 3 or 4)
Pin 2 – Power supply
Pin 3 – Vout = Vin when Vin > Vthreshold
Pin 4 – Vout = Vin when Vin < Vthreshold
Pin 5 - GND


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).

Pin 3 to 1 is 1.5 ohms pin 4 to 1 is read as overloaded, but it is because there is noting to read there. The relay is only sending voltage and current to pin 3 not 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).

Click happened twice. Click happened around 6v on the way to 8v then on the way back to 0 at 2v

Video 1 shows when the click happens

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).

When the power supply is set at 0 before the switch that occurs at 6 v pin 3 reads a 5.02v and pin 4 reads a very small value of volts. After it clicks the the values for the pins switch pin 4 reads 5.02v and pin 3 reads a small voltage. They switch again at the 2v click.

Video 2 explain what happens when the click occurs

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)

Picture 1 circuit schematic of the LED/Relay circuit 

Video 3 show how to turn an LED light on/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)

Table 1.1 values of Vin and Vout from opamp with resistors 1 k ohms and 2 k ohms

Table 1.2 values of Vin and Vout from opamp with resistors 2 k ohms and 100 ohms

2. Use your temperature sensor as your input. Do you think you can generate enough voltage to trigger the relay? (EXPLAIN)

The temperature sensor has too much resistance so if we used hair dryer to heat it up, it wouldn't be enough heat to trigger the relay. Moreover,  The temperature sensor needs a source with a really significant heat that would generate enough voltage to trigger the rely. We think if we used temperature sensor with the OpAmp would generate enough voltage to trigger the relay.


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

Picture 3.1 Circuit Schematic 

Video 3.1 explanation of the Circuit Schematic and how the Circuit works.

4. BONUS! Show the operation of the entire circuit. (VIDEO)

Week 5 Lab

1. Functional check: Oscilloscope manual page 5. Perform the functional check (photo). 

Picture 1.1 shows the functional check for the 1st port on the oscilloscope

Picture 1.2 shows the functional check for the second port. 

2. Perform manual probe compensation (Oscilloscope manual page 8) (Photo of overcompensation and proper compensation). 

Picture 2.1 shows a functional check when the probe is overcompensation

Picture 2.2 shows a functional check when the probe is proper compensation

3. What does probe attenuation (1x vs 10x) do (Oscilloscope manual page 9)? 

Using 1x on the porobe limits the bandwidth to 7MHz where 10x uses the full bandwidth. The 10x also reduces the amplitude of the signal 10x more than 1x probe. The 10x also does not disrupt the circuit reading as much as the 1x which can change the waveform readings. The 1x probe is only better for reading low voltage measurements. 

 
4. How do vertical and horizontal controls work? Why would you need it (Oscilloscope manual pages 34-35)? 

By using vertical positioning knobs for graph one you can change where the displays on the y axis by moving up and down on the y axis. Using the horizontal knobs changes the view of the display left and right down the x axis. These allows us to shift the waveform on the display to get more accurate reading and to compare it to other waveforms.  

5. Generate a 1 kHz, 0.5 Vpp around a DC 1 V from the function generator (use the output connector). DO NOT USE oscilloscope probes for the function generator. There is a separate BNC cable for the function generator. 

a. Connect this to the oscilloscope and verify the input signal using the horizontal and vertical readings (photo). 

Picture5.1: shows the input signal using horizontal and vertical readings 

We generated a voltage of 560mV peak to peak on the osiclloscope by using the function generator.  By generating 0.25Vp and 1 KHz using the function generator.


b. Figure out how to measure the signal properties using menu buttons on the scope. 

By using the measure button on the oscilloscope which is located above the vertical adjustment nobs and to the left of the auto set button. Then on the display on the right of the screen you can use the buttons for each slots to change the variable the oscilloscope will measure and what channel it will measure from.  

Picture5.2 shows where the button is located 

6. Connect function generator and oscilloscope probes switched (red to black, black to red). What happens? Why? 

When we switch the connection between the probes of the function generator black and red with the probes of the oscilloscope the oscilloscope does not read anything because if we connect the red probe of the function generator to the clip of the oscilloscope the values sent from the function generator is sent to ground since the clip is the ground. 

7. After calibrating the second probe, implement the voltage divider circuit below (UPDATE! V2 should be 0.5Vac and 2Vdc). Measure the following voltages using the Oscilloscope and comment on your results: 

a. Va and Vb at the same time (Photo) 

Picture7.1:show  signal of Va and Vb  after measuring from the oscilloscope

  The first channel measured a small value which was 1 V and the second channel measures a bigger value which was 2V. 




b. Voltage across R4. 

 

Vb-Va=VR4
Since the the measurement of Vb is measurement of voltage across R4 and R5, and the measurement of Va is the measurement of voltage across R5. So Vb-Va should be the measurement of voltage across R4.
AC= 0.118V
DC= 1.337V




8. For the same circuit above, measure Va and Vb using the handheld DMM both in AC and DC mode. What are your findings? Explain. 

Table 8.1 shows the values obtain from measuring Va &Vb using the DMM in AC & DC modes. 

Since the the 5V DC should be equally spread across the resistor which should be a DC value of 1.67V across each resistors. Va is a measurement of just one resistor so it should be close to that value which we got 1.335V and the measurement across Vb is two resistors which should be 3.406V or just double the measurement of Va so using our value of Va Vb should be 6.670V we got 2.672V.

9. For the circuit below 
a. Calculate R so given voltage values are satisfied. Explain your work (video) 

Video9.1: show how we found R7

b. Construct the circuit and measure the values with the DMM and oscilloscope (video). Hint: 1kΩ cannot be probed directly by the scope. But R6 and R7 are in series and it does not matter which one is connected to the function generator. 

Video9.2: measuring resistance 

Video9.3: measuring resistance 

10. Operational amplifier basics: Construct the following circuits using the pin diagram of the opamp. The half circle on top of the pin diagram corresponds to the notch on the integrated circuit (IC). Explanations of the pin numbers are below: 

a. Inverting amplifier: Rin = 1kΩ, Rf = 5kΩ (do not forget -10 V and +10 V). Apply 1 Vpp @ 1kHz. Observe input and output at the same time. What happens if you slowly increase the input voltage up to 5 V? Explain your findings. (Video) 

  Video10.1: Explain what happens when we increase the voltage 

of the voltage when we increase the voltage of the input in an inverting amplifier.

When the input value(in Blue) increases from 0.5V to 5 V, The peak to peak value will increases until it reaches its maximum value which was in our video 9.5 Vpp and then the wave of the output  will round out. In our experiment we tried to increase the voltage of the input but the output value wouldn't change and Output voltage would read 5 Vrms.  

b. Non-inverting amplifier: R1 = 1kΩ, R2 = 5kΩ (do not forget -10 V and +10 V). Apply 1 Vpp @ 1kHz. Observe input and output at the same time. What happens if you slowly increase the input voltage up to 5 V? Explain your findings. (Video)

                                                            Video10.2: Explain what happens when we increase the voltage                                                            

    of the voltage when we increase the voltage of the input in a

Non-inverting amplifier.

it is like the inverted amplifier but in the non-inverted amplifier , the input voltage and the output voltage starts close to each other when the value is small but as the voltage increases, the output voltage increase greater and it is because the gain is higher. Until the maximum value is reached which is 9.6V, then it would round out and no matter how we increase the input value, the output voltage willn't increase.