Introduction to electric circuits including voltage, current and resistance.

1. Summary of Circuits E. Alexander Burt Potomac School

3. A conductor – a path for the current to flow. Usually this is a metal object.

4. A reason for the charge to move. This is provided by an electric field, and the electric field comes from a difference in voltage.

7. Voltage = work / charge

8. V=w/Q

9. Voltage is like height. In order for charge to flow through a conductor, there must be a difference in voltage between one end and the other.

13. In this case, it's a flow of charge over time. We use the letter I for current.

14. I=q/t

15. The unit for current is the Ampere (or Amp, for short.) One Amp is one Coulomb per second.

17. Resistance creates a voltage drop

18. The unit for resistance is the Ohm, and it is the ratio of the voltage drop to the current:

19. R=V/I

22. The larger the cross-sectional area, the lower the resistance.

24. Circuits must include a battery or power supply to make the charge move

25. There are equal voltage rises and drops, so the total voltage around the loop is zero.

27. Other components have symbols: http://castlelearning.com/review/reference/phys11.gif