Transcript
CGTC Lab #9 PHYS 1110
Series and Parallel Circuits Basics
Brittany Lowe
Directions:
Log on to your computer
Go to the following website:
http://phet.colorado.edu/index.php
Click the button that says “Play with sims…”
Click on the application that says Circuit Construction Kit (DC only). It should be the first box.
Click “Run now.”
Series Circuits
Build a simple series circuit that consists of 6 pieces of wire, 1 light bulb, and 1 battery (voltage source). In order to complete the circuit, the red circles at the end of each must overlap. Please note that the light bulb also has TWO circles. Your circuit is complete and working when the light comes on and the blue dots begin moving.
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What do you think that the moving blue dots represent? I think the moving blue dots are the electrons.
Use the tools at the side to get a voltmeter and a Non-contact ammeter. Put the voltmeter near the battery and place the red tab at one end and the black at the other.
What is the voltage? -9.00V
Place the ammeter crosshairs over the moving blue dots. What is the reading? 0.90A
What does this tell us about the circuit? The measurement of the electrons, flowing through the wires.
Use the left button to play with the resistance and voltage of the battery. Make observations on how this changes the readings on the voltmeter and ammeter. Record your observations below. Be sure to record the changes you made and then the effects.
Start: W/Resistance: 2.0 Ohms
Voltage: -9.00V Voltage: -7.50V
Ammeter: 0.90A Ammeter: 075A
Click the advanced tab and alter the resistivity of the wire. Record your observations.
During this observation, I noticed that the battery voltage reading went down. With the more resistance I added.
Parallel Circuits
Parallel circuits provide more than one path for electrons to move. Sketch below a parallel circuit that includes 10 wires, 2 light bulbs and 1 voltage source.
Use the voltmeter and non-contact ammeter to measure electron flow and push.
Voltage: __-9.00V_____ Ammeter: __0.45A____
How does this compare with your observations in the series circuit? Is this surprising? WHY or WHY NOT? The voltage and the ammeter have different readings. Yes, this is surprising, because I would think it will have the same ammeter reading too.
Alter resistance and voltage and record your observations below.
When adding one more battery the voltage and current is -9.00V and 0.90A. When adding 5.0Ohms of resistance the voltage and current went down to -6.00V and 0.60A.
Now right click on one of the wires connected to a light bulb. Remove the wire and record your observations.
When removing the wire from the bulb, the lights went out.
Does this affect the voltage, amperes, or visually change the appearance of the light bulb?
When disconnecting the wire, the voltage didn’t change. The amperes and the appearance of the light bulb visually all changed. The lights went out on the bulb.
Replace the wire. Now remove one of the wires touching the voltage source. What happened?
The light is off.
What is the difference between removing the first wire and the second? Why is this significant?
There is no difference between removing the first wire and the second.
Comparisons
Create a second series circuit and record your observations about the two once they are side by side.
You may use the tool to play around. Create a circuit using a switch. Diagram your circuit below and show your working circuit to the teacher to receive extra credit points.
My new diagram includes 5 wires, 3 bulbs and 1 battery. The voltage is -9.00V and 0.30A. this is different from my first diagram.
Record any observations below.
