1. Electric Current

2. Electric current
Electric current is the rate of electron flow past a specific point in the circuit (how fast electrons pass through a point in the wire).
The symbol for electric current is I.
The units of electric current is amperes or amps (A).

3. Electric current DC

4. Electric current AC

5. Electric current can be compared to the flow of water.

6. Electric current can be compared to water current:
Comparison
Water Current
Electric Current
Conductor
What is flowing
Units for flowing particles
Time interval
Rate of flow (current)
pipe or hose
wire
water molecules
electrons
Coulombs (C) of charge
(1 C = amount of charge on 6.25x1018 electrons)
Litres (L) of water
per second (s)
per second (s)
coulombs per second
1 ampere (A) = 1C/s
litres per second

7. How Electricity Works

8. How to use an AMMETER
AMMETERS are used to measure the ________________ in a circuit.
electric current

9. How to use an AMMETER I1
Example: We want to measure the current at I0 and I1 for the circuit below. I0
I0 the current coming from the power source.
I1 the current passing through the bulb. I1

10. How to use an AMMETER disconnected series
To measure the current at I0 or I1, the circuit must be _________________ to make the ammeter part of the circuit. The ammeter is then connected in _____________.
disconnected
series

11. How to use an AMMETER positive / red positive / red
Connect the terminal of the ammeter to the wire(s) leading to the ___________________terminal of the power source.
positive / red
positive / red

12. How to use an AMMETER negative / black negative / black
Connect the terminal of the ammeter to the wire(s) leading to the ___________________terminal of the power source.
negative / black
negative / black

13. How to use an AMMETER I1
To measure I0 :

14. How to use an AMMETER I1
To measure I1 :

15. How to Read an AMMETER

16. How to Read an AMMETER What is the reading on this ammeter?
If you connected the circuit to the 3A setting on the ammeter, then the current reading is 1.5 A.
If you connected the circuit to the 1A setting on the ammeter, then the current reading is 0.5 A.

17. How to Read an AMMETER What is the reading on this ammeter?
If you connected the circuit to the 3A setting on the ammeter, then the current reading is 2.15 A.
If you connected the circuit to the 1A setting on the ammeter, then the current reading is 0.72 A.

18. How to Read an AMMETER What is the reading on this ammeter?
If you connected the circuit to the 300 mA setting on the ammeter, then the current reading is 215 mA.

19. Electric Shock