1. Series/Parallel Circuits
Section

2. Concepts Studied So Far
Ohm’s Law: Victory Is Rare
Power: P=IV
KCL
KVL

3. Outline Resistors in Series→ Req Resistors in Parallel → Req
Voltage Divider Circuits →Voltage divider formula
Current Divider Circuits →Current divider formula

4. Resistors Connected in Series
Series-connected circuit elements carry
the same current

5. Equivalent Resistor
Req=R1+R2+R3….

6. Exercise
Identify the resistors connected in series

7. Resistors in Parallel
Parallel-connected circuit elements have the same voltage across their terminals

8. Equivalent Parallel Resistor
1/Req=1/R1+1/R2+1/R3+1/R4

9. Series Parallel Simplification

10. P3.5
Find Rab

11. P3.7
Find Rab

12. The Voltage-Divider Circuit
Function: to develop more than one voltage
level from a single voltage supply

13. A Voltage Divider Connected to a Load

14. The Current Divider Circuit

15. Example 3.3
Calculate power dissipated in the
6 Ohm resistor

16. Problem 3.14
vo(no load)=4 V
vo(load)=3 V
Find RL

17. 3.15 Assume that only 0.5 W resistors are available
The no-load voltage is to be the same as in the schematic.
Specify the smallest values of R1 and R2

18. Application: Photovoltaic System
Solar Cell
I-V Characteristics Equation
Series construction
Parallel construction

19. I-V Characteristics of a Solar Cell
Short Circuit
Current I(Isc)
Open Circuit Voltage (Voc)
I-V Characteristics shows all the possible operating point
for the solar panel

20. Open Circuit Voltage Measurement
Observation: there is no current at Voc.

21. Short Circuit Current Measurement

22. Why is OK to short circuit a solar cell?
It is possible to produce short circuit a solar panel because
The current comes from the electrons produced by the
solar cell. Only some of the photons striking the solar cell
are converted into current. The current produced by
the solar cell is finite.

23. Power Produced by Solar Cell
P=IV
Observation: No power is produced at
Voc and Isc. Why?

24. Example If Vmp is 15 V and Imp is 3A, what resistance is required
in order to operate the solar cell at its maximum power?
Answer: A 5 Ohm load.

25. Rule of Thumb
Solar cells are generally connected in series to achieve a desired voltage.
The serial connected solar cells are connected in parallel to build current and power.
Cells are connected to form modules and modules are connected to form array.

26. Connect Cells/Modules in Series
Individual cells are connected in series by soldering the metal strip
from top surface (- terminal) of one cell to the back surface (+ terminal)
of the next

27. Use Series Connection to Increase Voltage
You want to use cells of matching current capacity!

28. Use Parallel Construction to Increase Current
(Acquire proper voltage)

29. Increase Current Capacity by Connecting Cells in Paralell