3. Series Current

4. Series Voltage Drops In a series circuit the sum of the voltage drops across each resistor or device is equal to the potential difference applied across the combination (i.e. the battery voltage).

5. Series Resistance The total resistance of resistors in series is the sum of the individual resistances.

6. Series Resistance

7. Parallel Current In a parallel circuit the total current through the battery is equal to the sum of the current through the branches.

8. Parallel Resistance The inverse of the total resistance of resistors in parallel is the sum of the inverses of the individual resistances.

9. Parallel Resistance

10. Equivalent Resistance 3Ω + 12Ω = 15Ω What is the current I ? V=IR; I = V/R = 30V/15Ω = 2 A

11. Equivalent Resistance What is the current I ? V=IR; I = V/R = 48V/3Ω = 16 A

12. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22

13. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Left 1. Collapse series R 1, R 2, R 3 into R 1+2+3.

14. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Left 2. Collapse parallel R 4 with R 1+2+3 into R 1+2+3+4.

15. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Left 3. Combine series R 5 with R 1+2+3+4 into R 1+2+3+4+5.

16. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Left 4. I 5 = 72 V/R 1+2+3+4+5

17. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Right 1. Collapse series R 8, R 9 into R 8+9.

18. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Right 2. Collapse parallel R 7 and R 8+9 into R 7+8+9.

19. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Right 3. Collapse series R 7+8+9 and R 6 into R 6+7+8+9.

20. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Right 4. I 6 = 72 V/R 6+7+8+9

21. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Right 5. I s = I 5 + I 6

22. Descriptive Examples Example – Calculate the indicated currents (I s, I 5 ) and voltage (V 7 ) in the circuit below. Insert Fig. 7.22 Right 6. V 7 = 1/2 I 6 X R 7