PRE-LAB QUESTIONS
Please complete the following questions before coming to the lab, and bring your answers with you to the lab:
- What is Ohm’s law? Please include an equation with your answer.
- Fill in the blanks: Resistors in series have the same ________ while those in parallel have the same ________.
- For the following circuit, derive an equation for the voltage out (Vout) compared to the voltage in (Vin) as a function of R1 and R2. Show your steps. Hint: apply Ohm’s law to both Vout and Vin.
- If you wanted to measure the voltage across a circuit element, would you introduce the voltmeter in series or in parallel to that circuit element? Explain. What about an ammeter?
- Suppose you have solved a circuit which has some combination of resistors in parallel and in series by finding its equivalent resistance. If you plotted the voltage versus current for that circuit, what would the slope of that plot be equal to?
- In Kirchhoff’s Junction Rule, does current direction matter? Explain.
- In Kirchhoff’s Loop Rule, which values are positive and which values are negative when finding the sum of voltages for a closed loop? Does the direction of current affect the calculation at all?
- Consider the circuit in “Circuit_4” and calculate I1, I2, and I3. You will compare these theoretical values with the ones that you will obtain experimentally in this lab. You will need to show your calculations in Question 9 of the lab report.
Set yourself the following objectives for this lab:
- Understand how resistance, voltage, and current are related
- Explore the difference between adding resistors in series and parallel
- Use Ohm’s Law to predict the current in several different circuits
- Simplify circuit analysis by finding the equivalent resistance and solving for it experimentally
- Build and explore how voltage dividers work
- Apply Kirchhoff’s voltage and junction laws experimentally and theoretically to a circuit
The following shows the value of all the questions in this lab:
| Laboratory 2, Question Grading Scheme | Totals | |||
| Part 1 | Question 1 | Question 2 | Question 3 | |
| Points | /1 | /1 | /1 | /3 |
| Part 2 | Question 4 | Question 5 | ||
| Points | /1 | /1 | /2 | |
| Part 3 | Question 6 | Question 7 | ||
| Points | /1 | /1 | /2 | |
| Part 4 | Question 8 | Question 9 | Question 10 | |
| Points | /1 | /2 | /1 | /4 |
| Total number of points in this lab | /11 | |||
The following shows the value of all the tables and graphs in this lab:
| Laboratory 2, Results Grading Scheme | Totals | |||
| Part 1 | Results | |||
| Points | /1.5 | /1.5 | ||
| Part 2 | Results | Graph | ||
| Points | /0.5 | /2 | /2.5 | |
| Part 3 | Table 1 | |||
| Points | /1 | /1 | ||
| Part 4 | Table 2 | Table 3 | Table 4 | |
| Points | /1 | /1.5 | /1.5 | /4 |
| Total number of points in this lab | /9 | |||