1. Circuit Notes:

2. Series Circuits
1. Fill all of the R values into the chart.
R1 = 10 ohms S V I R R1 10 R2 20 R3 30 T
Vt = 30V
R2 = 20 ohms
R3 = 30 ohms

3. Series Circuits S V I R 10 20 30 T .5 60 Calculate Rt Plug in Vt
4. Calculate It
R1 = 10 ohms S V I R R1 10 R2 20 R3 30 T .5 60
Vt = 30V
R2 = 20 ohms
R3 = 30 ohms

4. Series Circuits
In series circuits, I’s are all equal.
Plug in I’s
Calculate Voltage Drops
Check to make sure they add up to Vt!
R1 = 10 ohms
Vt = 30V
R2 = 20 ohms S V I R R1 5 .5 10 R2 20 R3 15 30 T 60
R3 = 30 ohms

5. Parallel Circuits P V I R 20 30 60 T 10 Fill in R’s
Vt = 30V
R1 = 10 ohms
R2 = 30 ohms
R3 = 60 ohms
Fill in R’s
2. Calculate Rt remember to calculate the reciprocals!

6. Parallel Circuits 1/Rt = 1/R1 + 1/R2 + 1/R3 1/Rt = 1/20 + 1/30 + 1/60
Rt = 60/6 = 10 ohms!

7. Parallel Circuits P V I R 20 30 60 T 3 10 Plug in Vt
Vt = 30V
R1 = 20 ohms
R2 = 30 ohms
R3 = 60 ohms
Plug in Vt
4. Calculate It (ohm’s Law!)

8. Parallel Circuits P V I R 30 1.5 20 1 .5 60 T 3 10
Vt = 30V
R1 = 20 ohms
R2 = 30 ohms
R3 = 60 ohms
In a parallel circuit, all V’s are equal!
Fill in V’s.
Calculate I’s Check to make sure they add up to It!

9. Combination Circuits P V I R 20 10
Find the resistor farthest from the power source. Determine if it is Parallel or series.
If it is parallel:
Set up a parallel box.
Calculate Rp
(remember reciprocals!)
R1 = 10 ohms
Vt = 120V
R2 = 20 ohms
R3 = 20 ohms P V I R R3 20 R2 Rp 10
R4 = 40 ohms

10. Combination Circuits S V I R 10 40 T 60 P V I R 20 10
Find series resistiors.
Set up Series box.
5. Calculate Rt.
R1 = 10 ohms S V I R R1 10 Rp R4 40 T 60
Vt = 120V
R2 = 20 ohms
R3 = 20 ohms
R4 = 40 ohms P V I R R3 20 R2 Rp 10
Effective Circuit: Parallel resistors combined act as a single series resistor

11. Combination Circuits S V I R 20 2 10 80 40 T 120 60 P V I R 20 10Rp R4 80 40 T
120 60
R1 = 10 ohms
Vt = 120V
R2 = 20 ohms
R3 = 20 ohms
Plug in Vt.
Calculate It
Series I’s are the same!
8. Plug in I’s
9. Calculate V’s
R4 = 40 ohms P V I R R3 20 R2 Rp 10

12. Combination Circuits S V I R 20 2 10 80 40 T 120 60 P V I R 20 1 2 10Rp R4 80 40 T
120 60
R1 = 10 ohms
R2 = 20 ohms
R3 = 20 ohms
R4 = 40 ohms
Substitute the Rp row into the Parallel box.
V’s are equal in a parallel circuit.
Plug in V’s
Calculate I’s
Your done! P V I R R3 20 1 R2 Rp 2 10