Circuit PHET

Run this DC circuit construction simulation PHET:

https://phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuit-construction-kit-dc_en.html

Choose "Lab"

Part 1 - Lighting up a light bulb. Measuring the voltage across and the current through the light bulb

1. Set up a circuit to light up a light bulb. You will need a few pieces of wire, a battery (Voltage source), a switch and a of course a light bulb.

2. When you have lit your bulb (click on the black circle on the switch to close the switch), draw a circuit diagram of your circuit using the IB symbols on page 4 of your data packet. In the lower right corner of the PHET you will see two buttons, if you click on the circuit symbol of a cell, it will change the PHET to a circuit diagram. Note that IB uses slightly different symbols, so you will need to translate. Use the IB symbols.

3. Click on the battery and slide the slider to change the voltage. What happens to the speed of the electrons as you increase the voltage? Leave the battery at a voltage between 5 and 20. (Pick a different value from your partner)

4. Click on the lamp and slide the slider to change the resistance. What happens to the speed of the electrons as you increase the resistance? Leave the lamp at a value between 2 and 10. (Pick a different value from your partner)

5. Label your Battery with its voltage, and label your bulb with its resistance.

6. In the upper right hand corner with "Show Current" checked, try checking the "Electrons" box, and the "Conventional" box. What is the relationship between the two? We will use Conventional current in this class, but personally find the electron animation more illustrative. Draw arrows on your circuit diagram showing the direction of the conventional current. Label your cell terminals + and -. (The longer side is the +)

7. Now get the Voltmeter, out and measure the voltage across the light bulb. (Put on lead on one side of the bulb, and the other on the other side of the bulb. Voltmeters always compare one voltage to another - they always show voltage difference) Show where you connected the voltmeter in your drawn circuit to measure the voltage across the light bulb.

8. Now get the Ammeter (The one without the probe with two connections on it) and place it in series with the light bulb to measure the current through the bulb. You will have to perhaps use more bits of wire, and break a connection you have made to put the ammeter where it needs to go.

9. When you get the ammeter to work, draw where you put the ammeter to measure the current in your drawn circuit.

10. What is the resistance of the light bulb? - Use Ohm's law.

11. What is the power dissipated by the light bulb? - Use one of the power equations you learned in your video flip.

Part 2 - Series and Parallel Circuits

Series:

1. Make a circuit with one battery and three resistors in series. Try to make it look like the example in the noteguide. (Laid out that way) Make the current flow CW just like that example.

2. Click on the battery. Pick a random even voltage from 10 to 50.

3. Click on each resistor, giving them random values between 10 and 30.

4. Take the magic ammeter out (The one with the cross hairs) put the cross hairs on every component of the circuit. Notice that there is just one current in the whole circuit.

5. Draw a circuit diagram of the circuit you built in the PHET using IB symbols, and show the calculation of the current the way I showed you in the video flip.

6. Take out the voltmeter. Place it across the battery, then across each resistor. Write the voltage of each resistor next to the resistor.

7. Show the proper calculation of the voltage drops for each resistor the way I showed you

8. If you go CW around the circuit starting before the cell, the voltage across the cell is +, and all the changes across the resistors are -. What do all the voltage changes in a complete circuit of the circuit add up to? Show this calculation. (It is Kirchhoff's loop law)

Parallel

1. Make a circuit with one battery and three resistors in parallel. Try to make it look like the example in the noteguide.

2. Click on the battery and give it a unique voltage from 10 to 50 V

3. Click on the resistors, and give them random values between 2 and 20

4. Take out the voltmeter and measure the voltage across the battery and across each of the resistors. Notice that all the components are at the same source voltage. This is the way the wiring in your house is set up.

5. Take the magic ammeter out (The one with the cross hairs) put the cross hairs on every component of the circuit. Notice that the currents are all different.

6. Draw a circuit diagram of your PHET circuit using IB symbols. Show the calculation of all the possible currents in the circuit the way I showed you in the video flip.