This document discusses electricity, circuits, Ohm's Law, and series and parallel circuits. It defines key terms like resistance (R), current (I), and voltage (V) and explains how they relate according to Ohm's Law (I=V/R). It discusses how total resistance, current, and voltage are calculated for series and parallel circuits. Key facts about resistivity and how it affects resistance are also summarized. Diagrams and examples are provided to illustrate these circuit concepts.

1. Electricity
Ohms Law, Circuits
Series & Parallel Circuits

2. Electricity (Circuit)

3. Circuit Symbols

4. R – Resistance ( )
IRV 
Ohms Law

I– Current (Ampere Amps)
V - Voltage( Volts V )

5. What is R in Diagram A?
Ohms Law
What is R in Diagram B?

6. Ohms Law
Volts (V) Current (Amp) Total Resistance (Ω)
1.5 V 3 Ω
3.0 V 6 Ω
6.0 V 5 Amp
5 Amp 7 Ω

7. Resistivity
Resistivity – the resistance of conductors to flow
of current.
What could be the factors about conductors that
affect flow of current?
– Type of material
– Length
– Cross-sectional Area

8. Resistance of Conductor
A
L
R 
areasectional-cross-
conductorofLength
materialofyresistivit
A
L 


9. Resistivity of Some Conductors
Material Resistivity (Ω-m)
Silver 1.59 x 10-8
Copper 1.7 x 10-8
Gold 2.4 x 10-8
Aluminum 2.8 x 10-8
Polyethylene 108 -109
Glass 1010 - 1014
Hard rubber 1013

10. Series
Equivalent Resistance Re is equal to the
sum of the resistance of each resistor

11. Series
321 VVVVbattery 
Voltage of Circuit is equal to the sum
of voltage drops across each resistors.

12. Series
321 IIIIbattery 
Current supplied by the battery is equal to
the current that passes through each resistor

13. Analysis of Circuit

14. Parallel

15. Parallel
321 IIIItotal 

16. Parallel
321
1111
RRRRe


17. Problem:
A parallel circuit contains 2 resistors:
2Ω and 4Ω. The battery carries 24 V.
321 VVVVbattery 
Obtain Re , Ibattery , V1 ,V2 and I2
Parallel