Ohm’s Law – Everything In Life Relates To Pressure.

  • P=Watts – The rate of energy conversion
  • R=Ohms – The electrical resistance
  • I=Amps – The amount of electricity passing through a / any point
  • E=Volts – The potential electrical difference between point (A) and point (B)
I also found this humorous but very good visual explanation of Ohms law here
simple-ohms-law.jpg

Resistance Tables.

American Wire Gages (AWG) Sizes and Resistances

 

AWG wire
size (solid)

Area
CM*

Resistance per
1000 ft (ohms) @ 20 C

Diameter
(inches)

Maximum current**
(amperes)

0000

211600

0.049

0.46

380

000

167810

0.0618

0.40965

328

00

133080

0.078

0.3648

283

0

105530

0.0983

0.32485

245

1

83694

0.124

0.2893

211

2

66373

0.1563

0.25763

181

3

52634

0.197

0.22942

158

4

41742

0.2485

0.20431

135

5

33102

0.3133

0.18194

118

6

26250

0.3951

0.16202

101

7

20816

0.4982

0.14428

89

8

16509

0.6282

0.12849

73

9

13094

0.7921

0.11443

64

10

10381

0.9989

0.10189

55

11

8234

1.26

0.09074

47

12

6529

1.588

0.0808

41

13

5178.4

2.003

0.07196

35

14

4106.8

2.525

0.06408

32

15

3256.7

3.184

0.05707

28

16

2582.9

4.016

0.05082

22

17

2048.2

5.064

0.04526

19

18

1624.3

6.385

0.0403

16

19

1288.1

8.051

0.03589

14

20

1021.5

10.15

0.03196

11

21

810.1

12.8

0.02846

9

22

642.4

16.14

0.02535

7

23

509.45

20.36

0.02257

4.7

24

404.01

25.67

0.0201

3.5

25

320.4

32.37

0.0179

2.7

26

254.1

40.81

0.01594

2.2

27

201.5

51.47

0.0142

1.7

28

159.79

64.9

0.01264

1.4

29

126.72

81.83

0.01126

1.2

30

100.5

103.2

0.01002

0.86

31

79.7

130.1

0.00893

0.7

32

63.21

164.1

0.00795

0.53

33

50.13

206.9

0.00708

0.43

34

39.75

260.9

0.0063

0.33

35

31.52

329

0.00561

0.27

36

25

414.8

0.005

0.21

37

19.83

523.1

0.00445

0.17

38

15.72

659.6

0.00396

0.13

39

12.47

831.8

0.00353

0.11

40

9.89

1049

0.00314

0.09

 

The U.S. wire gauges (called AWG gauges) refer to sizes of copper wire. This table corresponds to a resistivity of

for copper at 20 C

*The AWG system states areas of round copper wires in “circular mils”, which is the square of the diameter in mils. 1 mil =.001 inch.

This data from Floyd, Electric Circuit Fundamentals, 2nd Ed.

**Maximum current for chassis wiring. Data from Handbook of Electronic Tables and Formulas for American Wire Gauge. The maximum current for power transmission is less.

 

Index Tables

Reference Floyd