Lab Day 11

Summing Amplifier Lab

In this lab assignment, we implemented a simple operational amplifier-based circuit. Since operational amplifiers are used commonly in circuits used to implement mathematical operations, we implement the processes of summing two voltages.

On the left side there is a schematic of the circuit with the measure resistance values. Below there is the equation used to find output voltage. On the right side there is a table showing Va with the measured and calculated values of output voltage and the percent error.

This is a picture of the circuit.

Difference Amplifier Lab

In this lab assignment, we implemented a simple operational amplifier-based circuit. Since operational amplifiers are used commonly in circuits used to implement mathematical operations, we implement the processes of taking the difference between two voltages.

On the left side there is a schematic of the circuit with the measure resistance values. Below there is the equation used to find output voltage. On the right side there is a table showing Va with the measured and calculated values of output voltage and the percent error.

This is a picture of the circuit.

Lab Day 10

Inverting Voltage Amplifier Lab

In this lab, we implemented a simple operational amplifier-based circuit. Since operational amplifiers are used commonly in circuits used to implement mathematical operations, we implemented the processes of multiplication by a negative constant.

This is the pre-lab with a picture of the circuit and the measured resistance values.

We measured the output voltage which was 3.71V and also calculated the output voltage which was 3.701V. The percent error was 0.24% because the values of the resistor was a little different

This is the table showing the input voltages and output voltages.

This is the graph showing input voltage vs. output voltage.

Lab Day 9

Non-Ideal Power Sources Lab

Though many theoretical models of electrical circuits assume that power supplies are ideal, actual circuit implementations can depend upon non-ideal limitations of the power supplies. In this lab, assignment we experimentally explored the behavior of non-ideal power sources. The experiments in this assignment illustrated some of the effects of non-ideal power supplies.

This is the pre-lab, we determined the expected values for the measured voltage out, source current, and power dissipated by the resistor for the cases when voltage source is ideal and non-ideal.

We then measured and recorded the actual value of the resistor for the circuit which is 22.3 ohms. We then used the waveform generator to apply the voltage 1V. We tuned the waveform generator voltage until we measure exactly 1V across the terminals. We then calculated the internal resistance of the voltage source as shown on the right side of the board.

Maximum Power Transfer Lab

This assignment involves the maximum power transfer theorem. We will inappropriately attempt to maximize the power delivered to a load resistor by, in some sense, re-defining the source circuit.

This is the pre-lab that we had to calculate the maximum power delivered to the load resistor.

This is a picture of the circuit.

We then calculate the maximum power with the measured value of the resistor and voltage.

Conclusion: The percent error was calculated as 0.70% from the expected value. This is because the value of the actual resistor was a little different. 

Lab Day 8

EveryCircuit

This is the first example we did during class. We had to use EveryCircuit do create our circuit that was given in class.

This was the second example that we did in class.

This is the third example we did in class to find the Thevenin Equivalent.

Thevenin's Theorem Lab

In this lab, we experimentally investigated Thevenin's Theorem. We first analytically determined a Thevenin equivalent for the given circuit and then we experimentally determined the Thevenin resistance and the open-circuit voltage necessary to create the Thevenin equivalent circuit.

This picture is from out pre-lab. We determined the Thevenin equivalent circuit, the open-circuit voltage and the Thevenin resistance. The voltage was 0.4579V and the resistance was 7.2K ohms. 

The circuit is on the left side of the board, the measured resistance values are in the middle. We also measured the voltage across terminals a-b and is given by 0.459V. The percent error was 0.24% compared to the actual value from the pre-lab.

We then measured the Thevenin resistance seen at terminals a-b which was 7.14K ohms. The percent error was 0.83% compared to the actual value from the pre-lab. 

We then picked a random resistor for RL which was 7.9K ohms and we connected it between the terminals a-b in the circuit. Then we found the voltage across and the load resistance.  

We then built the Thevenin equivalent circuit we determined in the pre-lab. We found the voltage across the load resistor and compared it to the voltage from the previous step.

On the last step, we connected a potentiometer between terminals a-b. We then measured and recorded the load voltage as a function of potentiometer resistance. 

These four pictures shows our circuit and measured values.

We then calculated the power delivered to the Vload as a function of the load resistance. The first column from the left side are the values of the measured resistance values, then the voltage measured, then the load resistance values, and finally the load power values. To calculate the load power we used the formula P = V^2 / Rl

We then used excel to plot the graph load power vs. load resistance.

Lab Day 7

Time-varying Signals Lab

In this lab, we focused using an arbitrary  waveform generator to generate time-varying signals and using an oscilloscope to measure time varying signals. This lab introduced the concepts necessary for application, measurement, and interpretation of time-varying signals.

This is the pre-lab, if R1=R2 these are the sketches using the input and output voltages. The top three graphs are the input voltages and the bottom three graphs are the output voltages. 

This is the waveform generator for the sinusoidal waveform. It provides the amplitude , period, and frequency.

This is the oscilloscope window, showing the amplitude , period, and frequency.

This is the waveform generator for the triangular waveform. It provides the amplitude , period, and frequency.

This is the oscilloscope window, showing the amplitude , period, and frequency.

This is the waveform generator for the triangular waveform. It provides the amplitude , period, and frequency.

This is the oscilloscope window, showing the amplitude , period, and frequency.

Conclusion: The graph shows the same images as we did during the pre-lab. The amplitudes for the output voltages are half of the input voltage. 

A BJT Curve Tracer Lab

In this lab, we had to investigate the collector current Ic vs. collector voltage, Vce characteristics of the BJT. We then configure the curve tracer.

This is a picture showing our circuit.

This is the setup from using the Waveforms AWG. Channel 1 which is the top graph is a triangular waveform. Channel 2 is the bottom graph that was put with the information provided by the directions.

This is the oscilloscope window of both graphs.

Using the scope in XY mode, we plotted channel 1 on the horizontal axis and channel 2 on the vertical axis. We see a set of 5 curves of Ic vs. Vce.

Questions Answered:

Ic = (2.5V) / (100ohms) = 0.025 A.

Ib= (2.5V - 0.7V) / (100K ohms) = 1.8 x 10^-5 A.

Vc = (0.025A) * (2.5V) * (2) = 0.125 V
Vb = (1.8 x 10^-5 A) * (2.5V) * (2) = 9 x 10^-5 V.

Lab Day 6

Quiz #2

We used Mesh Analysis to solve 3 unknowns with 3 equations.

Mesh Analysis III Lab

In this lab, we analyzed, built, and tested a circuit containing multiple sources. We used mesh analysis to predict the circuit behavior prior to building and testing the circuit. We then compared the measured values with the calculate values. 

On the top left corner, there is a schematic of the circuit labeled with meshes and values for mesh currents. On the bottom left corner, we have the measured resistance values. On the top right corner, are the 3 equations we came up with to solve 3 unknown currents. The values were I1=0.26, I2=-0.8, and I3=0.112 all in milliamps. We then calculated the value for V1 which was 2.45V. After all of these calculations, we built the circuit and measured that V1 was 2.43V. The percent error between the measured and expected value of V1 was 0.82%. 

This is a picture showing the circuit and the expected value of V1 which was 2.43V.

Conclusion: The percent error between the measured and expected value of V1 was 0.82%. The percent error was made because the measured resistance values were a little different. If the resistors measured the same values as we used in the calculations, then the answers would of been the same.

Lab Day 5

Nodal Analysis Lab

In this lab, we analyzed, built, and tested a circuit containing multiple sources. We used nodal analysis to predict the circuit behavior prior to building and testing the circuit. Then we compared the measured circuit with our calculated values.

This picture is from the pre-lab. We had to calculate the voltages from nodes 1-4 and found out that at node 2, V= -0.576V. We took this number to calculate the voltages V1 and V2 in the circuit as shown on the top right corner.

This is a picture showing the measured V1 which is equal to -2.39V.

This is a picture showing the measured V2 which is equal to -4.41V.

This is a picture showing the schematic of the circuit on the top left corner. The voltages at 4 different nodes on the bottom left. The calculated V1 and V2 on the top right corner. At last, the measured V1 and V2 on blue color.

Conclusion: After measuring V1 and V2, we calculated the percent error between the measured and expected values of V1 and V2. The percent error for V1 was 1.42% and V2 was 0.32%. This happened because the measured resistance values were a little off of what we were supposed to use.

Lab Day 4

Quiz #1:

Temperature Measurement System Lab

In this lab, we designed and constructed a temperature measurement system. The system used a thermistor to detect temperature changes. We created an electrical circuit which uses the resistance change to output a voltage which indicates the temperature of the thermistor.

This is a picture from the pre-lab, we used the graph to determine the temperature at 25 degrees Celsius and 37 degrees Celsius. From those temperatures, the resistances were 11,000 ohms and 7,000 ohms. The calculated resistances were 5,000 ohms and 15,400 ohms.

We used a 3000 ohms resistor and a 12,000 ohms resistor that was the closest resistor from the calculated value from the pre-lab. At room temperature the 3,000 ohms resistor was 1.032V and body temperature was 1.547V. At room temperature the 12,000 ohms resistor was 2.57V and body temperature was 3.20V.

  

Conclusion: This is a picture for the post-lab. The output sensitivity was off since the resistor used were lower than the calculated values for about 4.5%.

This is a picture of the circuit.

These are the videos of the operating circuit.