From Electric to Electronic

1
From Electric to Electronic

• From the JUs to the Vacuum Tube

2
Electric vs. Electronic

• Electric circuits are connections of conductive
  wires and other devices whereby the uniform flow
  of electrons occurs.
• Electronic circuits add a new dimension to
  electric circuits in that some means of control
  is exerted over the flow of electrons by another
  electrical signal, either a voltage or a current.
  
• In electronics we are dealing with special
  devices able to control the flow of electrons
  according to another flow of electrons, or by the
  application of a static voltage.
• In other words, in an electronic circuit,
  electricity is able to control electricity.

3
It all started with the first Ju
4
1st JU
"Ju-Got-Electricity-Ju-Got-Magnetism"
5
Coil them up!
6
2nd JU
"Ju-Got-Magnetisim-Ju-Got-Electricity"
7
Current Induced ONLY when moving!
8
How do you measure Inductance?

• The ratio of magnetic flux to the current
  producing it.

L F / I
Webers/Amperes
Inductance is measured in Henries
9
3rd JU
Ju-Got Electricity-Ju-Got-Magnetisim-Ju-Got-Elect
ricity"
Joseph Henry (1797-1878) is widely considered the
foremost American scientist of the 19th century.
Henry's early investigations concerned
electromagnetic phenomena, and his discovery of
electromagnetic self-induction in 1831
established his reputation in America. In 1846
Henry was named first Secretary of the
newly-established Smithsonian Institution, a
position he held until his death. In 1868 he was
elected President of the Academy this position,
too, he held until his death.
10
Can you picture it?!
11
Continuing with electronicsUsing electricity to
control electricity.
Thomas Alva Edison (February 11, 1847 October
18, 1931) was an American inventor, scientist and
businessman who developed many devices that
greatly influenced life around the world,
including the phonograph, the motion picture
camera, and a long-lasting, practical electric
light bulb. Dubbed "The Wizard of Menlo Park"
(now Edison, New Jersey) by a newspaper reporter,
he was one of the first inventors to apply the
principles of mass production and large teamwork
to the process of invention, and therefore is
often credited with the creation of the first
industrial research laboratory.
12
The Precursor to the Vacuum Tube

• Edison and his team were hard at work trying to
• find a light bulb filament that worked well. He
• had already settled on a carbonized (burned)
• bamboo filament, but even this solution was not
• perfect. After glowing for a few hours, carbon
• from the filament would be deposited on the
• inside walls of the bulb, turning it black.
• His assistant noticed that the carbon seemed to
  be coming from the end of the filament that was
  attached to the power supply, and seemed to be
  flying through the vacuum onto the walls of the
  bulb.
• Edison determined that not only was carbon flying
  through the vacuum, but that it carried a charge.
  That is, electricity was flowing not only through
  the filament but also through the evacuated bulb.

13
Thermionic Emission

• The flow of charged particles called thermions
  from a charged metal or a charged metal oxide
  surface, caused by thermal vibration energy
  overcoming the electrostatic forces holding
  electrons to the surface of the atom.

The Edison Effect
14
How to fix the blackened bulbs?

• Edison tried to draw off the discoloration by
  placing a metal plate and charging it POSITIVE
• Edison noticed that, with an extra electrode
  connected to the positive end of the filament, a
  small but measurable electric current flowed
  between them. He termed this device an Electrical
  Indicator.
• While he was proven to be right about the flow,
  Edison could not explain it, and the third
  electrode did not prevent blackening of the bulb,
  so he moved on to other experiments. But he did
  patent the new device, because he believed that
  it might have some commercial applications, such
  as measuring electric current.

15
20 years later

• Edison Effect in a vacuum tube was waiting to do
  something

16
Side Note - Galvanization

• Luigi Galvani 1783
• Italian physicist and physician
• He was a pioneer in modern obstetrics,
• and discovered that muscle and nerve cells
• produce electricity.

17
The Galvanometer

• Galvanometer is the historical name given to a
  moving coil electric current detector.
• When a current is passed through a coil in a
  magnetic field, the coil experiences a torque
  proportional to the current.
• If the coil's movement is opposed by a coil
  spring, then the amount of deflection of a needle
  attached to the coil may be proportional to the
  current passing through the coil.
• Such "meter movements" were at the heart of the
  moving coil meters such as voltmeters and
  ammeters until they were largely replaced with
  solid state meters.

18
Back to Business Mrs. Houston!
So what about this Galvano-froggy-thingy?
19
Aha!
20
The Fleming Valve

• Sir John Ambrose Fleming -1904
• Worked to develop the first rectifier while
  working for the Marconi
• Company.
• He was faced with the problem of detecting weak
  wireless signals.
• He was decided to try inserting one of Edisons
  lamps in
• an oscillatory circuit containing a
  galvanometer.
• He had found the solution to the problem of
  rectifying
• high frequency wireless circuits.
• Fleming designed a transmitter for to attempt
  transmission of
• radio waves across the Atlantic from Poldhu,
  England, to
• Nova Scotia, Canada.
• The distance between the two points was about
  3,500 kilometres (2,100 miles).

21
The Fleming Valve

• Allowed electrical current to flow in one
  direction, but not the other.
• Fleming determined that by changing the position
  of the
• metal plates around the filament he could vary
  the strength
• of the current.
• At the receiving end the radio waves were
  difficult to
• detect with a galvanometer, but Fleming realized
  that if
• he could get the current to flow in only one
  direction,
• the oscillations of the wireless signal could be
  read easily.
• He did this by adding a positively charged plate
  separate
• from the filament to the Edison tube.
• Fleming Valve, Diode Valve, Fleming Diode,
• Thermionic Valve, Oscillation Valve.
• It becomes known as a 'vacuum tube' in America

22
How The Fleming Valve Works
A negative charge to the plate causes the current
to cease. They are repelled by like charges.
Positive voltage on the plate attracts electrons
from the filament. Current flows!!!

-
23
Going One Way!

• The creation of the Fleming diode opened up
  electrical technology to both alternating current
  and direct current.
• Although now superceded by transistors and
  integrated circuits in electronic applications,
  diodes are still used in high-power transmitters,
  sensitive optical applications, and audio
  amplifiers.
• Rectification
• To convert alternating current into direct
  current.

24
But Wait Theres More!
25
Modulation Amplification!

• Lee de Forest 1906
• Modified Fleming's Valve by adding a grid to
  control
• and amplify signals, and called his device the
  Audion.
• His Audion tube, a three-electrode device
• (plate, cathode, control grid), was a vacuum
  tube
• which allowed for amplification for radio
  reception.
• This "grid" was a bent wire between the plate and
  filament. de Forest discovered that if he applied
  the signal from the wireless-telegraph antenna to
  the grid instead of the filament, he could obtain
  a much more sensitive detector of the signal. In
  fact, the grid was changing ("modulating") the
  current flowing from the filament to the plate.
• This device, the Audion, was the first successful
  electronic amplifier. It was the genesis of
  today's huge electronics industry.
• Audion, Triode

26
How A Triode Works
Apply a like charge to the grid and the flow
stops!! (Its that magnetism thing at work
again!!!)
27
So What?!

• A small electric current applied to the grid
  would result in the proportionate flow of a much
  larger current from the filament to the plate- in
  other words, amplification.
• The Audion became know as the Triode and was the
  standard means of amplification until it was
  gradually replaced by the transistor in the
  1950's and 60's.
• Without the Audion, inexpensive amplification of
  wireless voice transmissions would not have been
  possible, and Radio Corporation of America would
  have been a significantly different enterprise.

28
Modulation

• the process of varying a periodic waveform in
  order to use that signal to convey a message
• to vary the amplitude, frequency, or phase of (a
  carrier wave or a light wave) for the
  transmission of information (as by radio)

29
Amplification

• increasing the power and/or amplitude of a
  signal.
• Taking power from a power supply and controlling
  the output to match the input signal shape but
  with a larger amplitude.
• In this sense, an amplifier may be considered as
  modulating the output of the power supply.

30
Whos Your Daddy?!

• Lee de Forest
• The father of radio

31
Wake up.... That's all!!