EX3_OhmsLaw1 Clinton

pdf

School

St. Petersburg College *

*We aren’t endorsed by this school

Course

2049

Subject

Electrical Engineering

Date

Dec 6, 2023

Type

pdf

Pages

Uploaded by Hojland

Experiment 3 Circuit Components and Ohms Law PHY 1049L St. Petersburg College Group Name: Group 5 Members and Responsibility: Issac Cowley (Procedures) German Gonzalez (Data) Seth Mcentegart (Calculation) Hoang Nguyen (Analysis) Tony Tran (Aggregate)

Theory: Voltage, V [Volts] is created by separated positive and negative charges (hence batteries have a positive and a negative terminal). Current, I [Amps] is the rate at which the electrons are flowing. Resistance, R [Ohms] is a material’s tendency to resist the flow of current. These three fundamental characteristics of circuitry is related through Ohm’s Law. ?[?] = 𝐼𝑅 [𝐴][Ω] Benjamin Franklin, in the 18 th century, made incredible breakthroughs in the field of electricity when he was not helping draft the Declaration of Independence. He knew that subatomic particles moved to create current, but he just did not know if it was the positive or the negative charges that actually moved. He guessed it was the positive charges, and hence the convention was created that current flows from positive to negative. Unfortunately, he was wrong, but this convention is still used today. It was not until later that it was discovered that electrons are free to move in conducting material and that protons are tied to the nucleus. To measure current, the current needs to flow through the Ammeter (and ammeter resistance = 0 Ω ). To measure voltage, the voltmeter needs to go across something that created a voltage difference. It does this without altering the original path of the circuit. Hence, the voltmeter assumes an “infinite” resistance because current will always flow thro ugh the path of least resistance. In circuitry, resistors drop voltage creating this voltage difference. Think of current as water flow starting from a mountain top and think of the resistor as a waterfall that drops voltage. The current is the same along any path, but the voltage will change depending on where your “waterfalls” are in the circuit. Well, what if there are no waterfalls? With no resistance, Ohm’s law tells us we have an infinite current. Essentially, we just destroyed our circuit. The amount of power in our circuit is given to us by 𝑃 = 𝐼? = ? 2 𝑅 [?] R eference Table Symbol Name Ω resistance A Ampere V Volt W power

Part (1): Circuit Components Procedures: 1) Go to the following link https://phet.colorado.edu/sims/html/circuit-construction-kit- dc/latest/circuit-construction-kit-dc_all.html . Select “Lab” and construct the following circuit as you see below. It consists of a battery, wire, a resistor, an ammeter (measures current), and a voltmeter (measures voltage). 2) Set the battery to 10.0V and the resistor to 10.0 Ohms. Turn on “Labels” and “Values” 3) Click on “Show Current – Electrons”. Is the movement of electrons (known as current) going clockwise or counterclockwise? Is the current going through the ammeter? Is it going through the voltmeter? Refer to the theory section as to why your observations occur. The movement of electrons is going counterclockwise. It is also going through the ammeter but not the voltmeter because the ammeter’s resistance is zero, whereas the resistance of voltmeter is usually very large. 4) Now Click on “Show Current – Conventional”. This shows the movement of positive charge (which doesn’t actually move) . Which direction is this going? The movement of positive charges, on the other hand, is going clockwise. 5) Turn off “Show Current”. Now change the position of the voltmeter probes so the black end is before the resistor, and the red end is after the resistor. What is the voltage reading now? In circuitry, “red” means it goes toward the +end and “black” means it goes towards the “ground”. The voltage after changing the voltmeter probes is -10 V. 6) Set the resistance of the resistor to 0 Ω and observe what happens to the current reading, voltage reading, and battery. Current: 99921.8 A, a very large number of current. Voltage: 0 V Battery: 10 V but it gets damaged.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

7) Bump your resistance to 0.1 Ω and observe what happens. This is what can happen when something has way too much current. It’s a bit exaggerated for small scales, but you still can physically feel low resistance resistors get hot. Current: 99.9 A Voltage: -9.99 V Battery: 10 V and it is burning. Part (2): Ohm’s Law 1) Set the voltage to 10V. Set the resistor to 10 Ω . Select the “Advanced” options and bring the wire resistivity a little pas t the zero mark. The exact position doesn’t matter. Measure the current and record in table 1. Complete the table below. Table 1: Raw Data V = 10.0 Volts Resistance [ Ω] 10.0 15.0 20.0 25.0 30.0 Current [A] 0.92 0.63 0.48 0.39 0.32 2) Create a formatted plot of Resistance vs 1/Current COPY/PASTE PLOT HERE

R ( Ω ): the resistance V (V): the voltage across the resistor I (A): the current through the circuit. 3) What is the experimental value for voltage to the correct number of sig figs and units? 𝑅 = ? 𝐼  The value of U is the slope of the graph of Resistance vs 1/Current. ? 𝑒𝑥𝑝 = 9.9 (?) 4) Find the Percent Error in voltage % 𝛿 𝑣 SHOW WORK % 𝛿 𝑣 = |10 − 9.9| 10 × 100% = 1% 5) Set the voltage to 10V. Set the resistance to 10 Ω . Measure the current and record in table 2. Complete the table below. Table 2: Raw Data R = 10.0 Ω Voltage [V ] 10.0 15.0 20.0 25.0 30.0 Current [A] 0.92 1.38 1.84 2.31 2.77 6) Create a formatted plot of Voltage vs Current COPY/PASTE PLOT HERE y = 9.8888x - 0.6611 R² = 0.9993 0 5 10 15 20 25 30 35 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 Resistance [ Ω ] 1/Current [1/A] Resistance (R) vs 1/Current (1/I)

R ( Ω ): the resistance V (V): the voltage across the resistor I (A): the current through the circuit. 7) What is the experimental value for Resistance to the correct number of sigfigs and units? U = IR  The value of R is the slope of the graph of Voltage vs Current. 𝑅 𝑒𝑥𝑝 = 10.8 (Ω) 8) Find the Percent Error in voltage % 𝛿 𝑅 SHOW WORK % 𝛿 𝑅 = |10 − 10.8| 10 × 100% = 8% Part (3): Analysis 1) In the lab, what did you find that represented the amount of precision you were able to obtain in the experiment? Precision measures how close the repeated experiment values are. So, we can set different values of wire resistivity to obtain the corresponding results. If the results are similar to each other, that indicates the high precision. 2) If the y-intercept was set to zero, how would it have impacted the precision or accuracy of your results? It would not affect the precision or accuracy of the results because the desired value we want to determine is the slope of the graph, which only depends on the data not the y-intercept. y = 10.799x + 0.0867 R² = 1 0 5 10 15 20 25 30 35 0 0.5 1 1.5 2 2.5 3 Voltage (V) [v] Current I [A] Voltage (V) vs Current (I)

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

3) What type of uncertainty was introduced into the experiment by increasing the wire resistivity? This uncertainty is the cause of your percent error. The wire resistivity is a source of systematic error because the wires always have resistivity no matter how good the material in the wires is, for example silver wires. 4) In order to account for your uncertainty, what would the resistance of the wire be in order to satisfy Ohm’s Law for the circuit ? To satisfy Ohm’s Law for the circuit, we can assume the resistance of the wire is zero. 5) How much power is in the circuit when the voltage was at 10V and the resistance at 10 Ω ? P = V  I = 10  10 = 100 (W)

Related Documents

ECEN 248-504 Lab 3 Report.docx

Exam1_answers.pdf

Homework_5.docx

Test #4_ 2023FL ENGR-1201-40002.pdf

ECE 200 Lab 4 (072621).pdf

Fall2023 Resistance and Resistivity Lab Online.pdf