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)

Week 5

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

Above is the Oscilloscope from page 5.  

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

Above is the same picture used in question #1! 

Above is the overcompensated oscilloscope. 

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


Basically, when attenuation is set to 1x the max bandwidth is 7 MHz.  For full usage of the bandwidth it must be at 10x.  The default setting is 10x, so the smaller it is the more accurate it will be.  

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

Vertical: 
Changes the display of the waveform to on and off, selects scale factors, and displays waveform math operations.  

Horizontal: 
Adjusts math waveforms and the horizontal position of a channel.   

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).



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

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

The black wire in the scope has a very hard ground so anything connecting to it is going to be ground. and the small wire in the function generator is going to short the generator.  There is no current going through the circuit because it is shorted.  


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)

b. Voltage across R4.

1 V.  R4 + R5 = 2 V, R5 = 1 V, so R4 = 1 V.  

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.

	DC(V)	AC(V)
Va	1.75	0.12
Vb	3.42	0.24

The voltage across each resistor is 1.67DC V. we get 1.75 V across R5 (Va), and get 3.42V across R5 and R4 combined. 3.42-1.75=1.67V so that will be the voltage across R4 which is near to our calculated value for AC.


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



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.




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:
1: DO NOT USE 8: DO NOT USE
2: Negative input 7: +10V
3: Positive input 6: output
4: -10 V 5: DO NOT USE

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)

As we increase the voltage, the amplitude on the input and the output gets larger.  This makes sense because on the graph the larger the voltage the larger the amplitude will be.  The amplitudes will eventually cross into each other but that is no problem.  The input and the output are opposites of each other, which again makes sense because -1V and +1V cancel to make zero, as well as -5 V and +5 V.  

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)

The non-inverting amplifier measures the same as the inverting amplifier.  This makes sense to me because all we were changing is the circuit set up, we aren't changing any voltage inputs or outputs.  Also as we increase our voltage up to 5 volts the amplitude again gets larger, which makes sense because the amplitude is the voltage measurement.  In channel 2 the peak is 6 volts. As we increase to 5 volts channel 2 (output) levels off at 6 volts while the input voltage keeps increasing.  

Week Four

1. (Table and graph) Use the transistor by itself. The goal is to create the graph for IC (y axis) versus VBE (x axis). Connect base and collector. DO NOT EXCEED 1 V for VBE. Make sure you have the required voltage value set before applying it to the base. Transistor might get really hot. Do not TOUCH THE TRANSISTOR! Make sure to get enough data points to graph. (Suggestion: measure for VBE = 0V, 0.5V, and 1V and fill the gaps if necessary by taking extra measurements).

Ic (mA)	Vbe(mV)
0	0
0	230
0.012	520
5.6	640
10.5	725

Table1;. Ic VS Vbe

Graph1;. Ic VS Vbe

2. (Table and graph) Create the graph for IC (y axis) versus VCE (x axis). Vary VCE from 0 V to 5 V. Do this measurement for 3 different VBE values: 0V, 0.7V, and 0.8V.

VCE	VBE	IC (mA)
0 V	0 V	0
1 V	0 V	12.1
2 V	.7 V	21.6
3 V	.7 V	29.78
4 V	.8 V	35.9
5 V	.8 V	48.8

3. (Table) Apply the following bias voltages and fill out the table. How is IC and IB related? Does your data support your theory?

VBE	VCE	IC	IB
0.7 V	2 V	10.1 mA	35.9 mA
0.75 V	2 V	12.7 mA	43.4 mA
0.8 V	2 V	17.9 mA	48.8 mA

4. (Table) Explain photocell outputs with different light settings. Create a table for the light conditions and photocell resistance.

No Light	Room Light	Flash Light
30 kΩ	1.78 kΩ	30 kΩ
The resistance keeps increasing as we were making the light darker.  The highest resistance we could get was 30 kΩ and that was in total darkness	With nothing covering the photo resistor, the resistance was 1.78 kΩ.	We used the flashlight from and iPhone 7 plus, and the lowest resistance we could achieve was .37 kΩ.

5. (Table) Apply voltage (0 to 5 V with 1 V steps) to DC motor directly and measure the current using the DMM.

Voltage (V)	Current (mA)
1.08 V	25.03 mA
2.04 V	32.02 mA
3.02 V	37.1 mA
4.02 V	40.1 mA
5.11 V	46.1 mA

6. Apply 2 V to the DC motor and measure the current. Repeat this by increasing the load on the DC motor. Slightly pinching the shaft would do the trick.

With there being no pinch, the current was 32.6 mA.  With the slight pinch, the current jumped to 69 mA.  

7. (Video) Create the circuit below (same circuit from week 1). Explain the operation in detail.

(Operation is explained in the video)

8. Explain R4’s role by changing its value to a smaller and bigger resistors and observing the voltage and the current at the collector of the transistor.

The voltage won't ever change, but when a higher resistance is applied, a lower current is measured, and when a lower resistance is applied, a higher current is measured.  

9. (Video) Create your own Rube Goldberg setup.

In our Rube Goldberg set up, we used the same circuit that was created in week 1 with the photo - resistor.  We applied 10 V from outlets A and B and once the flashlight is shined on the photo - resistor, the motor drags the ping pong ball up the ramp.