A Brief Historyof Electricity

Discussion D1.1

Some Electrical Pioneers

• Ancient Greeks

• William Gilbert

• Pieter van Musschenbroek

• Benjamin Franklin

• Charles Coulomb

• Alessandro Volta

• Hans Christian Oersted

Some Electrical Pioneers (cont.)

• Andre-Marie Ampere

• Michael Faraday

• Joseph Henry

• James Clerk Maxwell

• Heinrich Hertz

• J. J. Thomson

• Albert Einstein

Some Electrical Inventors

• Samuel F. B. Morse (Telegraph)• Guglielmo Marconi (Wireless telegraph)• Thomas Edison (Electric lights …..)• Nikola Tesla (A.C. generators, motors)• John Bardeen and Walter Brattain

– Transistor

• Jack Kilby and Robert Noyce – Integrated Circuit

• Marcian (Ted) Hoff (microprocessor)

Ancient Greeks – Static Electricity

Rub amber with wool.Amber becomes negatively charged by attracting negative charges (electrons) from the wool. The wool becomes positively charged.

The amber can then pick up a feather.How?

William Gilbert (1544-1603)

Coined the word “electricity” from the Greek word elektron meaning amber.

English scientist and physician to Queen Elizabeth.

In 1600 published "De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure" ("On the Magnet, Magnetic Bodies, and the Great Magnet of the Earth").

Showed that frictional (static) electricity occurs in many common materials.

Pieter van Musschenbroek (1692 – 1761)Dutch physicist from Leiden, Netherlands, who discovered capacitance and invented the Leyden jar.

Ref: http://chem.ch.huji.ac.il/~eugeniik/history/musschenbroek.htm

Leyden jar (also called condenser)

Leyden Jars

http://www.alaska.net/~natnkell/leyden.htmhttp://home.earthlink.net/~lenyr/stat-gen.htm

Refs:

700 pF, 175 KV

Q = C x V = 700 x 10-12 x 175 x 103

= 1.225 x 10-4 coulombs

No. of electrons =1.225 x 10-4 coulombs / 1.6 x 10-19 coul/elec= 7.66 x 1014 electrons

Benjamin Franklin (1706 – 1790)Conducted many experiments on static electricity from 1746 – 1751 (including his lightning experiment) and became famous throughout Europe by describing these experiments in a series of letters to Peter Collinson.

Charles Coulomb (1736 – 1806)Using a torsion balance Coulomb in 1784 experimentally determined the law according to which charged bodies attract or repel each other.

Coulomb’s Law

1 21 122

0 12

1

4

q q

rF e

7 2 9

0

110 9.0 10

4c

Unit: Newton meter2 / coulomb2

volt meter / coulomb

Alessandro Volta (1745 – 1827)Interpreted Galvani’s experiment with decapitated frogs as involving the generation of current flowing through the moist flesh of the frog’s leg between two dissimilar metals.Argued with Galvani that the frog was unnecessary.

In 1799 he developed the first battery (voltaic pile) that generated current from the chemical reaction of zinc and copper discs separated from each other with cardboard discs soaked in a salt solution.

The energy in joules required to move a charge of one coulomb through an element is 1 volt.

Hans Christian Oersted (1777 – 1851)

Ref: http://chem.ch.huji.ac.il/~eugeniik/history/oersted.htm

1822

In 1820 he showed that a current produces a magnetic field.

X

André-Marie Ampère (1775 – 1836)French mathematics professor who only a week after learning of Oersted’s discoveries in Sept. 1820 demonstrated that parallel wires carrying currents attract and repel each other.

attract

repel

A moving charge of 1 coulomb per second is a current of 1 ampere (amp).

Michael Faraday (1791 – 1867)Self-taught English chemist and physicist discovered electromagnetic induction in 1831 by which a changing magnetic field induces an electric field.

Faraday’s electromagneticinduction ring

A capacitance of 1 coulomb per voltis called a farad (F)

Joseph Henry (1797 – 1878)American scientist, Princeton University professor, and first Secretary of the Smithsonian Institution.

Discovered self-induction

Built the largest electromagnets of his day

Unit of inductance, L, is the “Henry”

James Clerk Maxwell (1831 – 1879)Born in Edinburgh, Scotland;Taught at King’s College in London (1860-1865) and was the first Cavendish Professor of Physics at Cambridge (1871-1879).

Provided a mathematical description of Faraday’s lines of force.

Developed “Maxwell’s Equations” which describe the interaction of electric and magnetic fields.

D

0 B

t

B

E

t

D

H J

Predicted that light was a form of electromagnetic waves

D E B H

“From a long view of the history of mankind - seen from, say, ten thousand years from now - there can be little doubt that the most significant event of the 19th century will be judged as Maxwell's discovery of the laws of electrodynamics. The American Civil War will pale into provincial insignificance in comparison with this important scientific event of the same decade”.

-- Richard P. FeynmanThe Feynman Lectures on PhysicsVol. II, page 1-11

What do Maxwell’s Eqs. Predict?

D Corresponds to Coulomb’s Law

D E electrical permittivity

24Area of sphere r

EqF E

What do Maxwell’s Eqs. Predict?

B = magnetic flux density (magnetic induction)

magnetic permeability

B( )q v F B

0 B

B H

Magnetic field lines must be closed loops

Force on moving charge qLorentz force

What do Maxwell’s Eqs. Predict?

t

B

E Corresponds to Faraday’s law of electromagnetic induction

A changing magnetic flux B density induces a curl of E

The rate of change of magnetic flux through an area A induces an electromotive force (voltage) equal to the line integral of E around the area A.

Motors and generators are based on this principle

What do Maxwell’s Eqs. Predict?

corresponds to Ampere’s Law

0D E permittivity of free space B

t

D

H J

0 B J

0B H

X

00permeability of free space

0 0 0 t

E

B J JExtra term added by Maxwell

What do Maxwell’s Eqs. Predict?

0 0 t

E

B

In free space (J = 0)

t

B

E

22

0 0 2t

EE

These two equations can be combined to form the wave equation

Solutions to this equation are waves that propagate with a velocity c given by

8

0 0

13 10 m / secc

(the speed of light!)

James Clerk Maxwell (1831 – 1879)

By the time that Maxwell died in 1879 at the age of 48 most scientists were not convinced of his prediction of electromagnetic waves. They had never been observed. No one knew how to generate them or to detect them.

Predicted that light was a form of electromagnetic waves

They would be discovered by Heinrich Hertz in 1887 and this would eventually lead to radio, television, and cell phones….

Heinrich Hertz (1857 – 1894)

The frequency of electrical signals is measured in hertz (cycles/second)

Generates and detects electromagnetic waves in 1887

Ref: http://www.sparkmuseum.com/HERTZ.HTM

Sir Joseph John Thomson (1856 – 1940)Discovers the electron in 1898

J. J. ThomsonCathode Tube

Cavendish Labs

Electric Field -- “corpuscle”

Albert Einstein (1879 – 1955)In 1905 publishes his Special Theory of Relativity based on two postulates:

1. Absolute uniform motion cannot be detected by any means.

2. Light is propagated in empty space with a velocity c which is independent of the motion of the source.

This theory predicts seemingly unusual effects such as the measured length of moving bodies and time intervals being dependent on the frame of reference being used for the measurement.

“It is well known that if we attempt to apply Maxwell's electro-dynamics, as conceived at the present time, to moving bodies, we are led to asymmetry which does not agree with observed phenomena. Let us think of the mutual action between a magnet and a conductor. The observed phenomena in this case depend only on the relative motion of the conductor and the magnet, while according to the usual conception, a distinction must be made between the cases where the one or the other of the bodies is in motion. If, for example, the magnet moves and the conductor is at rest, then an electric field of certain energy value is produced in the neighborhood of the magnet, which excites a current in those parts of the field where a conductor exists. But if the magnet be at rest and the conductor be set in motion, no electric field is produced in the neighborhood of the magnet, but an electromotive force which corresponds to no energy in itself is produced in the conductor; this causes an electric current of the same magnitude and in the same direction as the electric force, it being of course assumed that the relative motion in both of these cases is the same”.

Opening paragraph of “On the Electrodynamics of Moving Bodies,” by Albert Einstein, Annalen der Physik 17 (1905), p. 891.

Some Electrical Inventors

• Samuel F. B. Morse (Telegraph)

• Guglielmo Marconi (Wireless telegraph)

• Thomas Edison (Electric lights …..)

• Nikola Tesla (A.C. generators, motors)

• John Bardeen and Walter Brattain– Transistor

• Jack Kilby and Robert Noyce – Integrated Circuit

The TelegraphSamuel F. B. Morse

(1791 – 1872)

The TelegraphSamuel F. B. Morse

(1791 – 1872)

Wireless Telegraph

Guglielmo Marconi Marconi Spark TransmitterBuilt at the Hall Street Chelmsford Factory

September, 1897

Electric LightsThomas Edison

1847 - 1931Replica of original lightbulb

Patent #223,898Invented and developed complete DC electric generation and distribution system for city lighting systems

Carried on a major competition with George Westinghouse who developed an AC generation and distribution system

Alternating Current (AC) SystemsNikola Tesla1856 - 1943 Over 700 patents

Rotating magnetic field principle Polyphase alternating-current system Inducton motor AC power transmission Telephone repeater Tesla coil transfromer Radio Fluorescent lights

The FirstPoint-Contact

Transistor1947

Bell Labs Museum

The FirstJunction Transistor

1951

Bell Labs

Lab model

M1752Outside the Lab

Texas Instrument’s First IC -- 1958

Jack Kilby

Robert NoyceFairchildIntel

Electronics, Volume 38, Number 8, April 19, 1965

Moore’s Law

Moore's Law(As predicted by Gordon E. Moore in 1965)

1

100

10000

1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975

Year

Tra

nsi

sto

rs

Moore’s Law

Moore's Law(Doubling every 2 years)

0.001

0.01

0.1

1

10

100

1000

10000

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Year

Tra

nsi

sto

rs (

in m

illio

ns

)

8080

286

486 Pentium

Pentium II

Pentium 4

64K

1M

4M

16M

Memory

Microprocessor

Moore’s law

• Wow– This growth rate is hard to imagine, most people

underestimate– How many ancestors do you have from 20

generations ago• i.e., roughly how many people alive in the 1500’s

did it take to make you?• 220 = more than 1 million people

Graphical illustration of Moore’s law

1981 1984 1987 1990 1993 1996 1999 2002

Leading edgechip in 1981

10,000transistors

Leading edgechip in 2002

150,000,000transistors

• Something that doubles frequently grows more quickly than most people realize!– A 2002 chip can hold about 15,000 1981 chips inside itself

This year’s transistors are just twice the size of a virus

Nick TredennickGilder Technology Report

Intel 4004

source: Computer Museum

http://www.blinkenlights.com/pc.shtml

January 1975cover ofPopular Electronics

Time's Man of the Year

(1982)

Moore's Law leads to need forElectronic Design Automation (EDA)

Moore's Law(Doubling every 2 years)

0.001

0.01

0.1

1

10

100

1000

10000

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Year

Tra

nsi

sto

rs (

in m

illio

ns

)

8080

286

486 Pentium

Pentium II

Pentium 4

64K

1M

4M

16M

Memory

Microprocessor

Electronic Design Automation (EDA)

• PSpice – analyze analog circuits– SPICE (Simulation Program with Integrated Circuits

Emphasis)

– 1970s: SPICE – Nagel and Pederson

– 1980s: PSpice – Microsim Corp.

– 1998: Merged with OrCAD

Electronic Design Automation (EDA)

• Verilog – Digital Design– 1984: Gateway Design Automation Inc. – 1990: acquired by Cadence Design System– 1995: Verilog becomes an IEEE Standard

• VHDL – Digital Design– V: VHSIC (Very High Speed Integrated Circuit) – HDL: Hardware Description Language – Developed under government contract in the 1980s– 1987 (1993) IEEE standard (IEEE 1076)