1. DC Circuits

2. Series & Parallel

3. Two bulbs connected in series

4. Two bulbs connected in parallel

5. Series Circuit One pathway for the current to flow
Current is the same for the components connected in series
Voltage is shared between the components connected in series

6. Parallel Circuit Multiple (split) pathways for the current to flow
Current is shared between the components connected in parallel
Voltage is the same for the components connected in parallel

7. Why do we get more current in the parallel circuit?

8. Adding resistors
When resistors are added in series, the total resistance increases.
But when resistors are added in parallel, the total resistance decreases.

10. Which wire has more resistance?

11. Resistors in Series
RT = the total resistance (aka “effective” resistance or “combined” resistance)

12. Resistors in Parallel

13. Example: Calculate RT
WARNING: DO NOT attempt to solve this by only using a calculator. YOU MUST SHOW WORKING.

14. Try this – Find the total resistance
2 kΩ
9 kΩ
3 kΩ
500 Ω
9 kΩ
6 kΩ

15. Series vs. Parallel
Which is better?

16. Example – Series Circuit
300 Ω
100 Ω
8 V
Find the total resistance.
Find the current flowing through R1
Find the voltage drop across R1
Find the voltage drop across R2

17. Example – Parallel Circuit
470 Ω R2
100 Ω
15 V
Find the total resistance.
Find the current flowing through the cell.
Find the current flowing through R1
Find the current flowing through R2

18. Finish Worksheet #4