Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy.

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details.

Like this presentation? Why not share!

9,117 views

Published on

No Downloads

Total views

9,117

On SlideShare

0

From Embeds

0

Number of Embeds

7,898

Shares

0

Downloads

29

Comments

0

Likes

1

No embeds

No notes for slide

- 1. 8/9/2011<br />Revision02<br />1<br />What is electricity?<br />
- 2. Voltage: electrical pressure <br />Current: flow of negative charges <br />Resistance: opposition to current flow<br />8/9/2011<br />Revision02<br />2<br />There are three basic properties of an electrical circuit:-<br />
- 3. VOLTAGE is electrical pressure<br />CURRENT is a flow of electrons and occurs only if there is a voltage and a path for the electrons. <br />8/9/2011<br />Revision02<br />3<br />
- 4. Resistance<br />RESISTANCE is opposition to current flow. A conductor has a low resistance; an insulator has a high resistance. <br />8/9/2011<br />Revision02<br />4<br />
- 5. 8/9/2011<br />Revision02<br />5<br />The Atom<br />
- 6. ATOMS<br />Electrons in energy levels<br />The same number of Electrons as Protons<br />No electrical charge<br />8/9/2011<br />Revision02<br />6<br />
- 7. In electrical studies the nucleus remains the same, no protons are added or lost.<br />The nucleus charge is never changed.<br />An atom will only gain or lose an electron or electrons.<br />This gain or loss will be in the outer shell.<br />Valency shell<br />If an atom has a charge it becomes an ION<br />8/9/2011<br />Revision02<br />7<br />ATOMS<br />
- 8. Like charges repel<br />Unlike charges attract<br />The electrons are pushed from one object and pulled to the other object.<br />This push/pull or force is called an emf (voltage).<br />Units Volts, Symbol V (E)<br />By the way, the effective speed of the electron flow is 7.5 times around the world in 1 second<br />8/9/2011<br />Revision02<br />8<br />Remember<br />
- 9. 8/9/2011<br />Revision02<br />9<br />
- 10. 8/9/2011<br />Revision02<br />10<br />
- 11. (+) ION<br />The ion has lost an electron<br />The total electrical charge is (+)<br />8/9/2011<br />Revision02<br />11<br />
- 12. (-) ION<br />This ion has gained an electron<br />The total electrical charge is (-)<br />8/9/2011<br />Revision02<br />12<br />
- 13. If the terminals have an external conducting path, the battery will continue to take electrons from the (+) terminal and place them on the (-) terminal.<br />The thing to understand is:<br />Electrons are NOT created or destroyed.<br />They simply flow around the conducting path (circuit). <br />8/9/2011<br />Revision02<br />13<br />WHEN A SOURCE(battery) IS ADDED<br />
- 14. ELECTRON FLOW<br />When a conducting path is added the additional electrons will move to the free spaces (holes) where electrons are missing<br />8/9/2011<br />Revision02<br />14<br />
- 15. The electrons flow from (-) to (+). ELECTRON FLOW<br />The flow of electrons is called CURRENT.<br />CONVENTIONAL CURRENT Flow is (+) to (-).<br />Conventional Current flow is the Australian Standard. <br />The unit of measurement is the ampere we use Amps<br />The symbol is A<br />8/9/2011<br />Revision02<br />15<br />Current<br />
- 16. 8/9/2011<br />Revision02<br />16<br />Resistance<br />A circuit must have an opposition to electron flow. Or the very high current would cause major problems.<br />This opposition is called RESISTANCE.<br />Measuring Unit - Ohm<br />Symbol - W<br />
- 17. The voltage is 240 volts.<br /> V = 240V<br />The current is 10 amperes<br />I = 10A <br />The resistance is 200 ohms<br /> R = 200W<br />8/9/2011<br />Revision02<br />17<br />Examples <br />

No public clipboards found for this slide

×
### Save the most important slides with Clipping

Clipping is a handy way to collect and organize the most important slides from a presentation. You can keep your great finds in clipboards organized around topics.

Be the first to comment