1. Ch.22-CURRENT ELECTRICITY

2. CURRENT A flow of charged particles – electric current.
A river of electrical energy that moves through a wire
Must have a closed continuous loop to work
Charges flow from higher potential difference to lower

3. Terms to Know: Current Battery Resistance Ammeter Voltmeter
number of charges that travel per second
Battery
voltage (source)
Resistance
impedes current
uses energy
Ammeter
measures current
Voltmeter
measure voltage
 measured in Amperes
Amps or A
measured in Volts
Volts or V
 measured in Ohms
ohms (W)
measures Amps
measures Volts
Terms to Know:

4. SCHEMATICS A sketch of what the circuit looks like
Represents how the current will flow in the circuit
Specific types of symbols for sketches
p. 597

6. Simple electric circuit shown pictorially and schematically.

7. OHM’S LAW
Ohm defined how current(amps), voltage(volts), and resistance(ohms=W) relate
V = I R
V : voltage of battery (e.g. 9 V battery)
I : current (number of charges per second)
R : resistance (e.g. light bulb, stereo, etc.)

8. Remember: Power is energy per time (P=E/t)
P = I2 R = V2/ R = I V
P : power (Watts)
I : current (Amps)
R : resistance (W)
V : voltage (Volts)
Remember: Power is energy per time (P=E/t)

9. Practice Problems Total of FIVE problems p594 #1-5  pick one
p600 #12 & 14 or #13 & 14  pick one or the other (2 problems)
p603 #23-25  pick one
Total of FIVE problems

10. CIRCUITS PARALLEL SERIES current has multiple paths to follow
broken circuit may not stop electrical flow
voltage is the same through each resistor
current adds for each
SERIES
current has only one path to follow
broken circuit stops all flow of electricity
current is the same through each resistor
voltage adds for each

11. CH 22 HW
Watts; J Amps; 9 Volts, 4.5 Watts; 1.6x104 J Watts Volts W; 60 W; 2 Amps 82. $513/kWh Amps; 12 Amps; when it is on

12. Ch.23: Series and Parallel Circuits

13. Review: SCHEMATICS A sketch of what the circuit looks like
Represents how the current will flow in the circuit
Specific types of symbols for sketches
p. 597

14. Review: CIRCUITS PARALLEL SERIES current has multiple paths to follow
broken circuit may not stop electrical flow
voltage is the same through each resistor
current adds for each
SERIES
current has only one path to follow
broken circuit stops all flow of electricity
current is the same through each resistor
voltage adds for each

15. Review: OHM’S LAW
Ohm defined how current(amps), voltage(volts), and resistance(ohms=W) relate
V = I R
V : voltage of battery (e.g. 9 V battery)
I : current (number of charges per second)
R : resistance (e.g. light bulb, stereo, etc.)

19. CIRCUITS PARALLEL current has multiple paths to follow
1/Requivalent = 1/R1 + 1/R2
voltage is the same Vtotal = V1 = V2
Voltmeters only
current adds for each Itotal = I1 + I2
SERIES
current has only one path to follow
Requivalent = R1 + R2
voltage adds for each Vtotal = V1 + V2
current is the same Itotal = I1 = I2
Ammeters only

20. kW W
W; 7.4 Volts; .88 Watts; 1.48 Watts
W; 1.7 Amps; 37 & 7.7 Volts; 63 & 13 Watts
W; 50 W; 19 Amps; 5.5 Amps; 2.2 Amps; 11 Amps
W; 13 W; 3.6 Watts
W;4.5 Amps; 2.5 Amps
CH 23 HW
Watts; J
Amps; 9 Volts, 4.5 Watts; 1.6x104 J
Watts
Volts
W; 60 W; 2 Amps
82. $513/kWh
92. 3 Amps; 12 Amps; part b
CH 22 HW

21. CIRCUITS LAB MATERIALS: OBJECTIVE: Switches Light bulbs Batteries
Wires
OBJECTIVE:
Determine the difference between the schematic and effects of series and parallel circuits

22. PROCEDURES Connect the battery, one bulb, a switch together
How bright is the bulb?
Repeat for the other bulb
Connect the battery, switch, and two bulbs in series
How bright are the bulbs?
PROCEDURES
Connect the battery, switch, and two bulbs in parallel
How bright are they?

23. SCHEMATICS Go back and draw a schematic for each set-up (4 drawings)
Remember that a schematic is not how it looks to us, but what the current sees
It helps to understand where the current is going
Be sure to use the proper symbols!!