INTRODUCTION TRANSISTOR CONSTRUCTION TRANSISTOR OPERATION

1
L
O
A
D
I
N
G
I
I
I
I
I
I
I
I
I
I
I
I
I
I
.
.
.
2
BIPOLAR JUNCTION TRANSISTORS
Introductionto Transistor Constructionand
Transistor Operation
3
Transistor

• a Current In/Current Out Device
• can either Sink Current or it can Source Current,
  it cannot do both.
• a device composed of semiconductor material that
  amplifies a signal or opens or closes a circuit.
• become the key ingredient of all digital
  circuits, including computers.
• Note Today's microprocessors contains tens of
  millions of microscopic transistors.
• Prior to the invention of transistors, digital
  circuits were composed of vacuum tubes, which had
  many disadvantages. They were much larger,
  required more energy, dissipated more heat, and
  were more prone to failures. It's safe to say
  that without the invention of transistors,
  computing as we know it today would not be
  possible.

4
Brief History of the Development of Transistors

• 1904 VACUUM TUBE
• the electronic device of interest
  and development
• introduced by J.A. Fleming
• 1906 LEE DE FROST
• Added a third element called control grid, to
  the vacuum diode, resulting in the first
  amplifier, the triode.

5
Early 1930sThe four element tetrode and
fiveelement pentode gain prominencein the
electron tube industry.1922-1937Radio and
television provided great stimulation to the tube
industry. Production rose from 1million(1922) to
about 100 million(1937)Following years The
industry became one of primary importance
6

• Rapid advances were made in..
• design
• manufacturing techniques
• high power and high frequency applications
• miniaturization

7
December 23, 1947 The following demonstrated
the amplifying action of the first transistor at
the Bell Telephone Laboratories. Dr. John
Bradeen PhD (Princeton) Dr. Walter H. Brattain
PhD (Univ.of Minnesota) Dr. William Shockley PhD
(Harvard) Original Transistor - a
point-contact transistor
8
Advantages of the three-terminal solid-
statedevice over the tube

• small and lightweight
• Had no heater requirement or heater loss
• Has rugged construction
• More efficient (less power was absorbed by the
  device itself)
• Instantly available for use
• No warm up period required
• Lower operating voltages were possible

9
All amplifiers (devices that increase the
voltage, current, or power level) will have at
least three terminals with one controlling the
flow between the two other terminals.
10
This was reported to you by
Joseph Anthony C. Sabal