The Transistor 1. How does a Transistor work The Bipolar Transistor The Field Effect Transistor 2. Comparing a Transistor to other devices Diode vs. the.

The TransistorThe Transistor1.1. How does a Transistor workHow does a Transistor work

The Bipolar TransistorThe Bipolar TransistorThe Field Effect TransistorThe Field Effect Transistor

2.2. Comparing a Transistor to other devicesComparing a Transistor to other devicesDiode vs. the TransistorDiode vs. the TransistorVacuum Tubes and Relays vs. the TransistorVacuum Tubes and Relays vs. the Transistor

3.3. Benefits of using transistorsBenefits of using transistorsAble to amplify an alternating signalAble to amplify an alternating signalUsed as a fast switchUsed as a fast switchLow PowerLow PowerSolid state and small in sizeSolid state and small in sizeInexpensiveInexpensive

4.4. First uses of TransitorsFirst uses of TransitorsReplaced Vacuum tubes in radios and computersReplaced Vacuum tubes in radios and computersHearing AidsHearing AidsAirplanesAirplanes

5.5. 4004 – First single chip Microprocessor where transistors 4004 – First single chip Microprocessor where transistors are integrated on a single piece of Siliconare integrated on a single piece of Silicon

DemonstrationsDemonstrations

►Vacuum Tube and CRTVacuum Tube and CRT►Silicon IngotSilicon Ingot► Individual TransistorsIndividual Transistors► Integrated Circuits with lids Integrated Circuits with lids

removedremoved►PBS - PBS - TransistorizedTransistorized

What is a TransistorWhat is a Transistor

Made of doped semiconductor materials, Made of doped semiconductor materials, the transistor is used to amplify electrical the transistor is used to amplify electrical signals or used as a switch.signals or used as a switch.

http://fourier.eng.hmc.edu

The DiodeThe Diode Forward Biased Forward Biased – Current flows – Current flows

The DiodeThe Diode Reverse Biased Reverse Biased::Electrons and holes swept away from the junction, so Electrons and holes swept away from the junction, so no current flows in the circuit.no current flows in the circuit.

The Bipolar NPN TransistorThe Bipolar NPN Transistor

The base-emitter junction is forward biased, the base-collector junction is reverse biased.

The transistor is bipolar because both charge carriers (holes and electrons) are present.

► By doping (adding impurities to) a semiconductor By doping (adding impurities to) a semiconductor material (i.e. Silicon or Germanium), very different material (i.e. Silicon or Germanium), very different electrical properties are created.electrical properties are created.

► By sandwiching these dissimilar materials, a By sandwiching these dissimilar materials, a transistor is made.transistor is made.

► If the base is thin, electrons from the emitter are If the base is thin, electrons from the emitter are swept though the base to the collector. Electrons in swept though the base to the collector. Electrons in the collector then respond to the positive voltage the collector then respond to the positive voltage and flow out of the collector.and flow out of the collector.

Basic Amplifier Circuit using the Basic Amplifier Circuit using the NPN Bipolar TransistorNPN Bipolar Transistor

http://www.tpub.com

Model of first Transistor c. Model of first Transistor c. 19471947

http://www.porticus.org/bell

Fabricating a transistor on a Fabricating a transistor on a single piece of doped siliconsingle piece of doped silicon

wikipedia

CNN.com

The Field Effect Transistor The Field Effect Transistor (FET)(FET)

Electricity Electricity flows from flows from the Source the Source to the to the Drain when Drain when an electric an electric field is field is applied to applied to the Gate.the Gate.

Field Effect Transistor (FET)Field Effect Transistor (FET)

FETs are tiny FETs are tiny switches that can switches that can open and close open and close very quickly.very quickly.

A negative A negative voltage will turn voltage will turn this p-channel this p-channel transistor on. transistor on. ‘On’ means there ‘On’ means there is a connection is a connection between the between the Source and Drain.Source and Drain. http://www.answers.com

Before the transistor, there was Before the transistor, there was the Vacuum Tubethe Vacuum Tube

►Also used to Also used to amplify signalsamplify signals

►Also used as a Also used as a switchswitch

Electrons are “boiled” off the cathode andattracted to the anode because of the applied voltage.

A grid controls the electron flow.The signal to be amplified is connectedto the grid. A small signal controls a much larger voltage

http://www.privateline.com

Cathode Ray Tube (CRT)Cathode Ray Tube (CRT)Still is use TodayStill is use Today

Vacuum Tube, Electron Gun, Fluorescent Vacuum Tube, Electron Gun, Fluorescent Screen, and Coils which accelerate and Screen, and Coils which accelerate and deflect the electron beamdeflect the electron beam

Prior to Vacuum tube:Prior to Vacuum tube:

► No coast-to-coast telephone callsNo coast-to-coast telephone calls► Wireless Telegraph in use – Morse codes received and Wireless Telegraph in use – Morse codes received and

boosted using relays.boosted using relays.► Alternating Signals could not be amplified with relaysAlternating Signals could not be amplified with relays► Signals were sent over wires no farther than NY to Signals were sent over wires no farther than NY to

DenverDenver

Relay: switch that opensand closes and iscontrolled by currentin another circuit.Two settings: OPENAnd CLOSED

On or Off, current is either constant or it does not flow.

Applying a small varying signal (voice signal) here would not produce a varying signal in the top circuit.

http://www.porthcurno.org.uk/html/morsecircuit.html

Why was AT&T interested in the Why was AT&T interested in the Transistor?Transistor?

►Vacuum Tubes were unreliable for Vacuum Tubes were unreliable for amplifying signals in transcontinental amplifying signals in transcontinental telephone calls.telephone calls.

►Vacuum Tubes consumed a lot of Vacuum Tubes consumed a lot of power and got hot.power and got hot.

►Competition from other phone Competition from other phone companies made reliable and fast companies made reliable and fast phone service important.phone service important.

ENIAC in 1946ENIAC in 1946

► First electronic First electronic computercomputer

► Designed for the Designed for the ArmyArmy

► $500,000$500,000► >17,000 Vacuum >17,000 Vacuum

TubesTubes► 150 KW of power150 KW of power► Filled multiple Filled multiple

rooms (700 sq. rooms (700 sq. ft)ft)

► Soldered and Soldered and constructed by constructed by hand by the hand by the University of University of Penn.Penn.

Hearing Aids - the first Hearing Aids - the first commercial devices that used commercial devices that used

transistorstransistorsc. 1953c. 1953

http://blog.modernmechanix.com

Some Hearing Aids do not amplify Some Hearing Aids do not amplify sound:sound:

Cochlear Implants bypass portion of the Cochlear Implants bypass portion of the ear that is damagedear that is damaged

Cochlear Nerve sends auditory information to the brain.

Wikipedia

Cochlear Implant Cochlear Implant ComponentsComponents

1.1. Electrode Electrode ArrayArray

2.2. ReceiverReceiver3.3. Speech Speech

ProcessorProcessor4.4. TransmittinTransmittin

g Coilg Coil5.5. MicrophoneMicrophone

http://deafblind.com/cochlear.html

http://transistorhistory.50webs.com/maico.html

► Individual PartsIndividual Parts► Integration of parts required hand wiringIntegration of parts required hand wiring

Early Transistor Radio http://vintageradio.me.uk

The birth of the integrated The birth of the integrated circuit (IC)circuit (IC)

► 1947- using silicon as a transistor is discovered1947- using silicon as a transistor is discovered► 1959- Texas Instruments put 10 transistors on one piece 1959- Texas Instruments put 10 transistors on one piece

of silicon. First company to use Silicon instead of of silicon. First company to use Silicon instead of GermaniumGermanium

► Used in Apollo Program to achieve moon landing – Used in Apollo Program to achieve moon landing – transistors integrated on pieces of silicon offered lower transistors integrated on pieces of silicon offered lower power and weight. 1961-69power and weight. 1961-69

Intel 4004

The World’s first Microprocessor, made in 1971

Computer on a chip!

It had 2300 transistors and ran at 740 KHz.

It could execute 45 instructions.

Could execute 96,000 instructions per second

As powerful as the ENIAC

Where’s the chip?Where’s the chip?

http://www.computerhistory.org/semiconductor/

http://www.britannica.com

Chips can have millions of transistors built on a small piece of silicon.

CMOS stands for ‘Complimentary Metal Oxide Semiconductor’. This means CMOS chips contain both pMOS and nMOS transistors.

SourcesSources

http://www.pbs.org/transistor/http://www.pbs.org/transistor/