1 / 15

190 likes | 688 Views

Electric Power. Power is the rate that work is done or energy is transferred , that is Power = Power is measured in Watts, W. Electric power delivered to a circuit by a power supply is given by Power = Current x Voltage P = IV. Electrons do NOT leave the circuit-

Download Presentation
## Electric Power

**An Image/Link below is provided (as is) to download presentation**
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.
Content is provided to you AS IS for your information and personal use only.
Download presentation by click this link.
While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

**Electric Power**Power is the rate that work is done or energy is transferred, that is Power = Power is measured in Watts, W**Electric power delivered to a circuit by a power supply is**given by Power = Current x Voltage P = IV**Electrons do NOT leave the circuit-**Energy leaves the circuit through the different “resistors” in the form of light, heat, and any kind of work done by the appliance the current is running through. The rate that the energy leaves the circuit is the power output.**Examples**How much energy does a 75 W light bulb give off in five minutes? Power = Energy / time Energy = Power x time Energy = 75 W x (5 x 60) seconds Energy = 22500 J What is the power output of a 3 A motor running on regular house voltage? P = IV P = 3 A x 120 V P = 360 W**“Power” lines**P =IV • The higher the current, the more the wires in the circuit heat up, thereby “wasting” energy. This is a big problem when electric companies must provide electricity at great distances away from the power plants. • The solution: Electric lines that carry current great distances are at very highvoltage, so the current can be relatively small. P = IV**High Voltage / Low Voltage**TRANSFORMERS: devices that “step-up” the voltage at the power plant and then “step-down” the voltage at the customers’ location.**Even with very high voltage, there is still some current**running through those wires. Therefore, some electrical power (dissipated through heat) is lost. If the entire length of wire has a total resistance R, the power lost along the way is given by Power lost (dissipated) = I2R**Voltmeter- device to measure voltage**• The voltmeter is placed “in parallel” with the component whose voltage is being measured.**Ammeter- device to measure amps (current)**• The current must flow THROUGH the meter, therefore an ammeter is placed “in series” with the component whose current is being measured.**Ohmmeter- device to measure resistance**• Resistance is measured with the power OFF! 2.3 W**Parallel Circuit**Series Circuit Req = R1 + R2 + R3 + … Each bulb has the same voltage across it! That voltage is the voltage of the battery. However, the current splits up so that each bulb only receives a portion of the total current pushed by the battery. If one of the bulbs goes out, the others remain lit, and will have EXACTLY the same brightness (WATTS) as they did before the bulb went out. P = V2 / R Each bulb has the same current running through it! That current is the TOTAL current pushed by the battery, IT = Vbattery / Req If one of the bulbs goes out, they ALL go out!**Closed circuit**Open circuit

More Related