Description and objectives

In this activity you will

Build circuits in a simulated environment: TinkerCAD

Measure basic electrical quantities using a multi-meter (i.e., voltage and current)

Verify circuit behaviors with resistors in series and in parallel

You will use the simulated environment for this activity, www.tinkercad.comLinks to an external site.. If you haven’t created an account with TinkerCAD yet, you may do so by clicking the ‘Join Now’ button on the upper right corner of the page and following the steps. Once you have created an account and are logged into TinkerCAD, choose the ‘Circuits’ option and the click ‘Create new Circuit’ to get ready to create a new circuit.

Submission format

Centered at the top write the name of this activity. Centered in a line below it write your name. Below these, the rest of the activity starts, aligned to the left.Be very organized, neat, and professional. You should use consistent spacing, formatting, font, and style, as well as correct grammar and spelling.Please type the answers to various parts as instructed below. Neatly organize all your answers in a numbered list (with sub lists) corresponding to various parts (and subparts).You want the grader to find all your work in a convenient way lest you may lose points.

In the end, you will submit everything as a single, typed, PDF file.

Instructions

Complete the following parts

Part 0: DescriptionWrite a 2-3 sentence description of this activity in your own words, e.g., what are the various parts and subparts of it, what is the purpose of various parts, etc. (2 points)This is a long activity, we don’t want you to be lost in the details without having a bird’s eye view of its contents and objectives.

Part 1: ResistanceIn this part, you will identify the theoretical value of a resistor using its color code. For reference, the color codes chart is provided below.Complete the following for this part:Record the theoretical value of a resistor that has color code of brown/black/red/gold in the Ω units.

Now express the same resistor value in the kΩ units.

Part 2: Building a circuit with resistors in seriesHere is a circuit of two resistors in seriesComplete the following for this part:In TinkerCAD, build the above series circuit using a breadboard, a 9V battery, and two resistors. Use 250Ω and 500Ω as the resistance for the two resistors, respectively (i.e., R1 = 250Ω and R2 = 500Ω). Take a screenshot of your circuit, which you will submit for this part.

This is a voltage divider circuit. So, to verify how the battery voltage is divided across these two resistors, you will need to measure the voltage difference across each resistor. In TinkerCAD, add a multimeter to the circuit to measure the voltage across each resistor, one at a time. Take a screenshot of your set up to show how the multimeter is connected to the circuit for voltage measurement. Record and write the voltage difference across resistor R1, and R2, as V1 and V2 respectively. Make sure to include units. Calculate the total voltage as V=V1 V2. Does it match the voltage of the battery, i.e., 9V?

Based on the measured values, which resistor has a larger voltage difference across it, the one with larger resistance or smaller resistance?

What is the relation between the ratio of voltages differences V1/V2 and the ratio of resistances R1/R2 ? We are looking for an algebraic relation between V1/V2 and R1/R2, we don’t want you to just write the numerical value of these ratios. Hint: You’ll have to write Ohm’s law for each resistor separately, and then do an algebraic manipulation.

Calculate and report the total equivalent resistance of R1, and R2 in series. Make sure to include units.

Based on Ohm’s law and the equivalent resistance, calculate the current in the circuit. Make sure to include units.

Now, in TinkerCAD, use a multimeter to measure the current in the circuit. Take a screenshot of your set up to show how you connected the multimeter in the circuit for current measurement. Record the current that you have measured in TinkerCAD. Make sure to record the units too. How does this value measured from TinkerCAD compare to the calculated value from the previous step?

Often the lowest voltage point of the circuit (e.g., the negative terminal of the battery) is taken to be at zero volt, i.e., ground. Using this notion, the voltage at the left side of the circuit is 0 V. The voltage at the right side of the circuit is then 9V (due to the battery). What must be the voltage at the middle point between the resistors? Hint: You know the voltage difference (i.e., subtraction) between the middle point and the left end of the R1. And that is V1. Similarly, you know the voltage difference between the middle point and the right end of the R2. And that is V2. Using either of these you can calculate the voltage at the middle point. This is very simple arithmetic. Don’t over think! But this idea is important and will be used in the next activity.

Part 3: Building a circuit with resistors in parallelHere is a circuit for two resistors in parallelNow complete the following steps for this part:Build the above circuit in TinkerCAD, using a breadboard, a 9V battery, and two resistors, R1 = 250Ω and R2 = 500Ω (you will want to go back to the TinkerCAD homepage and click ‘Create new Circuit’ to start a new circuit for this part). Take a screenshot of your circuit, which you will submit for this part.

This is a current divider circuit. So, to verify that the total current coming from the battery is divided between the two resistors, you will need to measure the total current, as well as the current flowing through each resistor. In TinkerCAD, add a multimeter to the circuit to measure the current through the battery and through each resistor, one at a time. Take a screenshot of your set up to show how the multimeter is connected to the circuit for current measurements (NOTE: current measurement using multimeter is a lot trickier than voltage measurement, people often do this wrong and get high values of current, which lead to blown fuses in real life).Record and write the current through battery and resistors R1, and R2 as Itot, I1, and I2. Make sure to include the units.Does Itot=I1 I2 as measured by DMM?

Based on your measured values, which resistor has more current flowing through it, the one with larger resistance or smaller resistance?

What is the relation between the ratio of currents I1/I2 and the ratio of resistances R1/R2 ? We are looking for an algebraic relation between I1/I2 and R1/R2, we don’t want you to just write the numerical value of these ratios. Hint: You’ll have to write Ohm’s law for each resistor separately, and then do an algebraic manipulation.

Calculate and report the total equivalent resistance of the two resistors in parallel. Make sure to include the units.

Based on Ohm’s law and the equivalent resistance, calculate the current in the circuit. Make sure to include units.Does this calculated value agree with the measured total current value from TinkerCAD?

Rubric

Here is a point distribution and rubric for the parts above

Part 0: A description of this activity in your own words but covering all the parts and subparts (2 points)

Complete work for part 1 (2 points total)1 point for including the correct theoretical resistance value in Ω

1 point for including the correct resistance value in kΩ.

Complete work for part 2 (13 points total)2 points for including screenshot of the correct circuit

1 point for including correctly measured voltage V1 and correct arrangement of DMM1 point for including correctly measured voltage V2 and correct arrangement of DMM0.5 points for matching V=V1 V2 with battery voltage

0.5 points for answering which resistor has higher voltage difference

2 points for including correct answer about the relationship between the ratio of V1 and V2 and ratio of R1 and R2

1.5 points for including correctly calculated total resistance Rtot.

1.5 points for including correctly calculated total current using Ohm’s Law and agreeing it current measured by DMM below

2 points for including correctly measured current using DMM

1 point for correctly reporting the voltage at the middle point.

Complete work for part 3 (13 points total)2 points for including screenshot of the correct circuit

2 points for including the correctly measured total current Itot using correct DMM arrangement1.5 points for including correctly measured current I1 using correct DMM arrangement1.5 points for including correctly measured current I2 using correct DMM arrangement0.5 points for matching Itot=I1 I2

0.5 points for answering which resistor has higher current

2 points for including correct answer about the relationship between the ratio of I1 and I2 and ratio of R1 and R2

1.5 points for including correctly calculated equivalent resistance Rtot.

1.5 points for including correctly calculated total current using Ohm’s Law and agreeing it with Itot from DMM.