INTRODUCTION

We have learned what voltage, amps and resistance are now. However, what do these three things do for us? These three things are all part of what makes power or what allows us to actually do something with the electricity. Let's learn about power.

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OBJECTIVES

Learn about power
Learn about energy
Learn how voltage, amps, and ohms help to calculate power
Use voltage and amps to calculate power

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POWER

Watch the videos to learn about power.

https://learn.sparkfun.com/tutorials/electric-power/all

https://www.youtube.com/watch?v=VSpB3HivkhY

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ENERGY

Watch the video to learn about Energy which is power over time.

https://www.youtube.com/watch?v=SMPhh8gT_1E

We should note here, that AC voltage can be affected by what is called power factor or pf. Power factor will be discussed in module 2. So for now you do not need to worry about it. Power factor is not affected by resistive loads such as a light bulb. So in this lab, the power factor is 1.

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FORMULAS

Formulas

Calculating Power (AC)

$LaTeX: P=V\times I\times pf$

Calculating Power (DC)

$LaTeX: P=V\times I$

Alternative Equations

Formulas

$LaTeX: P\:=\:R\times I^2$

$LaTeX: P=\frac{V^2}{R}$

Variables

V = Voltage in volts (V) (This can also be displayed as E for electromotive force)
I = Current in amps (A)
R = Resistance in ohm's (Ω)
P = Power in watts (W)
pf = Power Factor

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MATERIALS + TROUBLESHOOTING REFERENCE PAGES

Materials Needed for this Lab

Multimeter
Extech Multimeter

Troubleshooting Reference Pages

Basic Electrical Trainer
Lockout Tagout
2-Way Switch
Circuit Breaker Box
Fan
Light Bulb
Light Socket
Power Supply
Single-pole Breaker
Wire
Wire Colors

Note: Keep this circuit wired up for the rest of module 1.

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TROUBLESHOOTING VIDEOS

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LAB INSTRUCTIONS

View the lab example video, and then perform the lab.

Use the Simple AC Light Circuit from Lab 1-2.
Measure the voltage across the light.
Measure the current through the light.
Calculate the power used by the light bulb.

	Note
	In this case, the Power Factor is 1.00, because the light is purely resistive.

Compare to the wattage of the light bulb (25 W).
Measure the voltage across the fan.
Measure the current through the fan.
Calculate the power used by the fan.

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SUBMISSION

Answer the questions in the quiz.