Download presentation

Presentation is loading. Please wait.

Published byPatience Hopkins Modified over 3 years ago

2
Voltage, Current, Resistance and Power

3
Voltage Voltage is the energy that moves the electrons through an electric circuit. Voltage is measured in J/C. In an electric circuit the voltage may be provided by a battery, a voltage source or a potentiometer. Cell or Battery Longer Line indicates positive Direct Current Voltage Source Potentiometer

4
Electric Current Any flow of charge is called an electric current. Current is measured in Amperes (Amps or A). 1 Amp = 1 C/s In electric circuits, we assume it is positive charges flowing through the circuit (conventional current). In reality, it is the electrons that flow. However in gases and liquids both positive and negative charges can flow.

5
Electrostatics & Circuits Example 19: Electric Current A steady current of 4.7 A exists in a wire for 180-s. a) How much total charge passed by a given point in the circuit during this time? b) How many electrons was this? The charge on one electron is 1.60 X 10 -19 -C {We can ignore the sign}

6
Electric Circuits All voltage sources have a positive “pole” and a negative “pole”. A battery produces current by repelling the electrons with the negative pole and attracting electrons with the positive pole. Current will only be produced if there is a closed path (circuit) for the electrons to flow from the negative pole to the positive pole.

7
+ - Conventional Current I When there is no closed path, a circuit for the electrons to follow from the negative pole of the voltage source to the positive pole of the voltage source, current will NOT flow!!!! But once the path is closed the electrons are repelled by the negative pole of the voltage source and attracted to the positive pole of the voltage source. Sorry, I didn’t know.

8
Electrostatics & Circuits Example 20: An Electric Circuit Which of the set-ups below will cause the bulb to light? No closed path from the negative pole of the battery, through the bulb, to the positive pole of the battery. Now there is a path from the negative pole of the battery, through the bulb and then to the positive pole. THE BULB LIGHTS UP!!!!!

9
Resistors & Resistance A property of all conductors is their ability to hinder the flow of electric current. This property is called resistance, R. The units for resistance are ohms, Ω. 1 Ω = 1 V/A Resistor OR

10
Ohm’s Law Georg Simon Ohm discovered that the resistance, R, was constant in many conductors. This is known as Ohm’s Law. Materials that obey Ohm’s Law are called ohmic. Materials that don’t obey Ohm’s Law are called nonohmic.

11
Electrostatics & Circuits Example 21: Ohm's Law A light bulb has 120-V across it and carries 0.012-A. a) What is the resistance of the bulb. b) Find the current through the bulb if the voltage across it is now 80-V. c) What voltage would be required to push 1.0-A through the bulb?

12
Electrical Power Electical Power is measured in Watts If the electrical Device is an Ohmic Resistor: OR

13
Electrostatics & Circuits Example 22: Electrical Power A light bulb has 110-V across it and a current of 0.5-A through it a)What is the power of this bulb? b)What is the resistance of this bulb?

Similar presentations

OK

Electrical Systems. VOCABULARYOBJECTIVES Series circuit Voltage drop Kirchoff’s Voltage Law Describe a series circuit. Calculate the resistance.

Electrical Systems. VOCABULARYOBJECTIVES Series circuit Voltage drop Kirchoff’s Voltage Law Describe a series circuit. Calculate the resistance.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To ensure the functioning of the site, we use **cookies**. We share information about your activities on the site with our partners and Google partners: social networks and companies engaged in advertising and web analytics. For more information, see the Privacy Policy and Google Privacy & Terms.
Your consent to our cookies if you continue to use this website.

Ads by Google

Ppt on leadership challenges Ppt on wireless solar mobile charger Ppt on series and parallel circuits worksheet Ppt on open cast coal mining Ppt on child labour free download Ppt on sf6 circuit breaker Ppt on 4 stroke diesel engine Ppt on virtual file system Ppt on conservation and management of forest Ppt on precautions of tsunami wave