The Nature Of Electricity

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The Nature of Electricity By Chuck Hobson g0mdk

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INTRODUCTION This “Nature of Electricity” presentation has been modified to include remarks normally used by a speaker as he proceeds through the slides. If you have any questions, you can email them to me and I will try to answer them. [email protected] (g zero mdk at tiscali.co.uk)

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CREDITS Elektrizität! Was ist es? L'électricité! Qu'est-ce que c'est ?

Georg Simon Ohm 1787 - 1854 André Marie Ampère 1775 - 1836 Charles Augustin Coulomb 1736 - 1806

Elettricità! Che cosa è esso? Electricity! What is it?

Count Alessandro Volta 1745 - 1827 Michael Faraday 1791 - 1867 James Watt 1736-1819 Joseph Henry 1797 – 1878 Nikola Tesla 1856 - 1943

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CREDITS Elektrizität! Was ist es? L'électricité! Qu'est-ce que c'est ?

Georg Simon Ohm 1787 - 1854 André Marie Ampère 1775 - 1836 Charles Augustin Coulomb 1736 - 1806

Elettricità! Che cosa è esso? Electricity! What is it?

Count Alessandro Volta 1745 - 1827 Michael Faraday 1791 - 1867 James Watt 1736-1819 Joseph Henry 1797 – 1878 Nikola Tesla 1856 - 1943

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CREDITS Elektrizität! Was ist es? L'électricité! Qu'est-ce que c'est ?

Georg Simon Ohm 1787 - 1854 André Marie Ampère 1775 - 1836 Charles Augustin Coulomb 1736 - 1806

Elettricità! Che cosa è esso? Electricity! What is it?

Count Alessandro Volta 1745 - 1827 Michael Faraday 1791 - 1867 James Watt 1736-1819 Joseph Henry 1797 – 1878 Nikola Tesla 1856 - 1943

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CREDITS Elektrizität! Was ist es? L'électricité! Qu'est-ce que c'est ?

Georg Simon Ohm 1787 - 1854 André Marie Ampère 1775 - 1836 Charles Augustin Coulomb 1736 - 1806

Elettricità! Che cosa è esso? Electricity! What is it?

Count Alessandro Volta 1745 - 1827 Michael Faraday 1791 - 1867 James Watt 1736-1819 Joseph Henry 1797 – 1878 Nikola Tesla 1856 - 1943

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CREDITS Elektrizität! Was ist es? L'électricité! Qu'est-ce que c'est ?

Georg Simon Ohm 1787 - 1854 André Marie Ampère 1775 - 1836 Charles Augustin Coulomb 1736 - 1806

Elettricità! Che cosa è esso? Electricity! What is it?

Count Alessandro Volta 1745 - 1827 Michael Faraday 1791 - 1867 James Watt 1736-1819 Joseph Henry 1797 – 1878 Nikola Tesla 1856 - 1943

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CREDITS Elektrizität! Was ist es? L'électricité! Qu'est-ce que c'est ?

Georg Simon Ohm 1787 - 1854 André Marie Ampère 1775 - 1836 Charles Augustin Coulomb 1736 - 1806

Elettricità! Che cosa è esso? Electricity! What is it?

Count Alessandro Volta 1745 - 1827 Michael Faraday 1791 - 1867 James Watt 1736-1819

Note they all have units of electricity named after them.

Joseph Henry 1797 – 1878 Nikola Tesla 1856 - 1943

THE ELECTRON

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FOUND IN ALL MATTER HEART OF ELECTRICITY SOME PROPERTIES •

Radius < 10-15 metres

•

Rest mass 9.1 × 10-28 grams

•

Charge neg. 1.6 × 10-19 Coulombs

HOW SMALL? A thousand trillion electrons side by side measure 0.5m HOW HEAVY? 1.2 thousand trillion trillion electrons weigh one gram HOW POTENT? 6.25 million trillion electrons make a 1 Coulomb charge

One Coulomb flowing per second = one Ampere. One gram of electrons contains 176,000,000 Coulombs of charge

PUTTING THE ELECTRON TO WORK

Note: Ideal model used, Wires have zero resistance, light illuminates instantly and resistance is a fixed 100 ohms.

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PUTTING THE ELECTRON TO WORK

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PUTTING THE ELECTRON TO WORK

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Note: If an oscilloscope and photo cell at the battery/SW end is triggered at SW closure, the photo cell & oscilloscope would see the light 6.67µs later.

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A QUESTION WHERE DID THE 3.3µs COME FROM? 1. 3.3µs was arrived at using a Radar type calculation •

Velocity x time results in distance travelled (v x t = d)

•

In Radar v = c, the speed of light- 300 million metres per seconds.

•

Radar range (c x t = d) 300 x 106ms-1 x 3.3 x 10-6s = 1000m (one way)

•

In our case we know d (1000m) and c, so we calculate t d 10 3 m −5 −6 t= = = 0.33x10 s = 3.3x10 s 8 −1 c 3x10 ms

Now consider current flow again

or 3.3µs

CURRENT FLOW

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100Ω

100Ω

100Ω

100Ω

CURRENT FLOW

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100Ω

100Ω

100Ω

100Ω

CURRENT FLOW

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100Ω

100Ω

100Ω

100Ω

Current measures 1A in fig 3. What about the current in figures 1 & 2?

CURRENT FLOW

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100Ω

100Ω 100Ω

100Ω

The battery doesn’t see the 100 ohm load in figures 1 & 2 All it sees is the characteristic impedance of the pair of wires In our example, this impedance is assumed to be 400 ohms.

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ANOTHER QUESTION Can electrons travel through wire at the speed of light ( c ) where c = 300,000,000 metres per second? 1. No way Jose! 2. Why not? Reason: 2. Electrons are particles with mass as previously stated 3. As particles approach c their masses increase enormously 4. This is in accordance with Einstein’s “Special Relativity” 5. This has been demonstrated at Cern and SLAC 6. Cern and SLAC use GeV’s to reach near c velocities 7. No particles including the electron have ever been accelerated to c

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ELECTRON VELOCITY-1 ELECTRON VELOCITY IN A VACUUM TUBE

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ELECTRON VELOCITY-1 ELECTRON VELOCITY IN A VACUUM TUBE

Formula from A-Level Physics

v=

e 2V m o

Calculation v = 1.759x1011 x2x2000 = 26.5 million metres per second (final velocity at the anode)

Let’s increase voltage on the Anode of the tube and calc. velocities

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ELECTRON VELOCITY-1

Anode voltage (kilovolts)

Electron Velocity million metres/s

Velocity to speed of light ratio

8.00

53.

0.177 (12.5%)

16.00

75

0.250 (25%)

64.00

150

0.500 (50%)

128.0

212

0.701 (70%)

256.0

300

1.000 (100%)

512.0

424*

1.410 (141%)

SOMETHING WENT WRONG! Electrons CANNOT exceed c! Increase in mass with velocity (relativistic mass) was not taken into account

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ELECTRON VELOCITY-2 When a mass velocity approaches the speed of light its mass increases This is in accordance with Einstein’s theory “Special Relativity” That is to say: relativistic mass (mr) = gamma ( γ ) times mo Relativistic mass calculations are done using the following formulas: #1

mr = γ x mo

#3

velocity v =

#4

v2 mr V= 2e

e 2V m r

where

#2

γ=

1 1−

v c

eV = 0.5m r v 2 eV = electron volt is a unit of energy used in particle physics

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ELECTRON VELOCITY-2 When a mass velocity approaches the speed of light its mass increases This is in accordance with Einstein’s theory “Special Relativity” That is to say: relativistic mass (mr) = gamma ( γ ) times mo Relativistic mass calculations are done using the following formulas: #1

mr = γ x mo

#3

velocity v =

#4

v2 mr V= 2e

e 2V m r

where

#2

γ=

1 1−

v c

eV = 0.5m r v 2 eV = electron volt is a unit of energy used in particle physics

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ELECTRON VELOCITY-2 When a mass velocity approaches the speed of light its mass increases This is in accordance with Einstein’s theory “Special Relativity” That is to say: relativistic mass (mr) = gamma ( γ ) times mo Relativistic mass calculations are done using the following formulas: #1

mr = γ x mo

#3

velocity v =

#4

v2 mr V= 2e

e 2V m r

where

#2

γ=

1 1−

v c

Known as the Lorentz Transform

eV = 0.5m r v 2 eV = electron volt is a unit of energy used in particle physics

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ELECTRON VELOCITY-2 When a mass velocity approaches the speed of light its mass increases This is in accordance with Einstein’s theory “Special Relativity” That is to say: relativistic mass (mr) = gamma ( γ ) times mo Relativistic mass calculations are done using the following formulas: #1

mr = γ x mo

#3

velocity v =

#4

v2 mr V= 2e

e 2V m r

where

#2

γ=

1 1−

v c

Known as the Lorentz Transform

eV = 0.5m r v 2 eV = electron volt is a unit of energy used in particle physics

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ELECTRON VELOCITY-2 Velocity m/s

Gamma

100,000,000

1.225

200,000,000

1.7320

250,000,000

2.4490

290,000,000

5.4770

299,000,000

17.320

299,999,000

547.72

299,999,999

17,219

On the last entry, notice the significant mass increase (x 17,219)

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ELECTRON VELOCITY-2 Velocity m/s

Gamma

Voltage

100,000,000.000

1.2250

34.8kV

200,000,000.000.

1.7320

197kV

250,000,000.000

2.4940

435kV

290,000,000.000

5.4770

1.31MV

299,000,000.000

17.320

4.4MV

299,999,000.000

547.72

140MV

299,999,999.000

17,219

4.4GV

299,999,999.999

547723

Voltages shown in the 3rd column required to obtain velocities in the first column. The point of this exercise is to show that it is virtually impossible to get the electron to move at the speed of light.

On the last entry, notice the significant mass increase (x 547723)

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A QUESTION REVISITED ELECTRONS DIDN’T TRAVEL AT c BUT THE SOMETHING DID 1. How about the “nudge” theory (cue ball effect etc.)?

Electrons out of the negative terminal nudge the next one on etc. The end result could be electrons at the light bulb 3.3µs later (?) There have been many arguments on this issue since the 1920’s A paper on this notion was submitted to the 1997 IEE.

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RECTANGULAR PULSE

WHAT IS HAPPENING DURING INTERVALS: (A – B), (B – C), (C – D)? (A – B) and (C – D)? Nothing! There is NO voltage or current B – C? 100V and 0.25A Note: Z of the transmission line pair = 400 Ohms. What would the situation be in 5.66µs?

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RECTANGULAR PULSE

Negative pulse moving back to the Pulse Generator

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SINGLE RECTANGULAR PULSE EXAMINATION RECTANGULAR PULSE Time Domain: Viewed on an Oscilloscope

Pulse reconstruction formula

f(t) =

1 τ

∫

+ 2 πa τ jωt A ( ω ) e d(t) − 2 πa τ

RECTANGULAR PULSE Frequency Domain: Viewed on a Spectrum Analyser

Fast Fourier Transform formula   A(f ) = 1  sin(πfτ)  = 1 sinc(πfτ) τ  (πfτ)  τ

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PULSE RECONSTRUCTION-1

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PULSE RECONSTRUCTION-2

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PULSE RECONSTRUCTION-3

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PULSE RECONSTRUCTION-4

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RECAP 1. The nudge (cue ball) explanation of conduction unresolved 2. Electrical energy travels ~ speed of light over wires to a load. 3. Likewise, pulses travel ~ the speed of light over wires. 4. Single pulses are made up of wide spectrums of frequencies 5. Pulse (spectrum of frequencies) travel as TEM signals at ~ c 6. In the circuit comprising a 100V battery, switch & light bulb: the leading edge of a pulse occurs at 100V switch on and the trailing edge of a pulse occurs at 100V switch off 7. Very long pulses have same properties as very short pulses 8. AC signals to µ-wave frequencies) travel as TEM modes 9. Note that the wave length of 50Hz = 6 million metres

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CONCLUSION

1. Electrical energy travels from source to load over wires as TRANSVERSE ELECTROMAGNETIC WAVES (TEM mode) 2. Current drift* (Amperes) is a consequence of EM Waves NOT THE OTHER WAY AROUND This may be difficult to visualize in a pair of wires, but if you consider EM microwaves travelling down a wave guide, there will be surface currents in the wave guide walls. These are also drift currents. They are also the consequence of EM energy

* A sample calculation of current drift is shown in appendix 1 of this presentation.

Appendix 1 ELECTRON DRIFT The current drift rate through a conductor is in the order of mm/s. The drift rate of 1A through a 1mm diametre copper wire is worked out as follows: Current density J = amperes per unit area (J = I/A) so J = 1Amp./(pi x r2) = 1/(3.14 x 0.00052) = 1.6 x 106 J can also be expressed as J = nevd Transposing: vd = J/(ne) Copper has an electron density n of 8.47 x 1028 m-3 With e = 1.6 x 10-19 coulombs of charge: ne = 1.4 x 109 Thus: vd = J/(ne) = (1.6 x 106) / (1.4 x 109) = 1.14mm/s

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That is the nature of Electricity as I perceive it. Thank you for attending Chuck Hobson BSc(hons) BA