physics lab

Experiment 4

1. Collaborators: Team 6

2. Objective: The purpose of this experiment is to understand how voltage is affected by the loop rule and node rule in different configurations of circuits. We will use Arduino measure the voltages across different circuit configurations where the resistors are either in series or parallel.

3. Experiment Description:

Set up (Ref. 1: video description):

1. Connect the ground pin from the Arduino to the main bus of the breadboard with a wire.

2. Connect the positive bus and the 5V slot with a wire. 3. Place the two 10 kilo-Ohm resistors in series on the breadboard

(from end to end). 4. From the positive bus (5V source), connect a wire to one end of

the resistors (not between them). Remember electrical connections on the rest of the breadboard run perpendicular to the bus.

5. Now connect a wire from the end of the 2nd resistor (again not between the resistors) to the ground (main bus).

6. Place a wire in the middle of the resistors and connect it to the Analog pin A0. This wire will be referred to as the measurement wire as you will use it to probe the voltage readings around the circuit.

7. Use the code in figure 1 (from the youtube video) for measuring voltage. Upload this to your Arduino IDE. Note that this code will be used throughout the experiment as it works regardless if the resistors are in series, parallel, etc. NOTE: You create this code by modifying AnalogInOutSerial found by the path: Open!Analog!AnalogInOutSerial in the Arduino IDE.

8. Connect your Arduino to your computer via USB. 9. Compile your code in the IDE by clicking verify (check mark

icon in top left). Then upload (run) the code to your Arduino (rightward pointing arrow).

10. Use the measurement wire to take the voltage reading around the resistors. NOTE: click the serial monitor in the top right corner to view your voltage readings.

11. After measuring the voltage for series, create a parallel circuit, and a combinational circuit of parallel and series and measure the voltage readings for both circuits. You should check voltages around the circuit; i.e. use the measurement wire to probe the voltage at the ends, in between the resistors, etc. NOTE: For a circuit with a combination of resistors in parallel and series you will need at least three resistors. It’s OK to use only two resistors for the first two configurations.

12. The youtube video in reference 1 is perhaps your greatest resource. These instructions are largely meant to supplement the directions on the video.

About Resistors in Series:  

In the series connection the head of one component is connected to tail of another component where the amount of current flow in all components is same and amount of voltage is the sum of all voltage drops in the circuit caused by each component.

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Where

Current I= I1=I2=I3

Voltage ΔV=V1+V2+V3

And

Equivalent Resistance=Req=R1+R2+R3

About resistors in parallel:

  In the Parallel connection all heads and all tails are respectively connected to the positive and negative terminal of the battery where the each branch and each component has the voltage at it. While the current is divided in each of the branch and total current is the sum of the current passing through each of the components, which is the complete inverse behavior to the series connection.

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Where

Current I= I1+I2+I3

Voltage : ∆V=V1=V2=V3

And

1/Req=1/ R1 + 1/R2 + 1/R3

So this is for the circuit with three resistors while the sum goes on with addition of each component.

Circuit will parallel and series configuration:

and

5. Equipment needed: Arduino Board, Arduino IDE, USB cable, breadboard, wires, three 10 kilo-Ohm resistors

6. Predicted outcome:

7. Online resources:

1. Should include date accessed. https://youtu.be/vINCP8Ri6kk?list=PLKHKgeIBVxp- ZGAbjZiyWOVq7Qki7USBq

Safety issues: Be careful when setting up the wires. They are sharp and are vulnerable to electric shock

FIG 1: Screenshot from video of code needed for voltage measurements.