The Drexel RET Program Research Experience for Teachers

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The Drexel RET ProgramResearch Experience for
Teachers

• The Drexel North Penn Collaboration
• Electronics Applications to Nanotechnology

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RET Experience Overview

• Provide experiential engineering education to
  K-12 teachers in the Delaware Valley region
  through laboratory discovery.
• Create innovative dissemination of gained
  knowledge to students and colleagues
• Work in Biotechnology, Information Technology, or
  Nanotechnology

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My Experience at Drexel University

• Worked in the Nanotechnology Field in the Fibrous
  Materials Research Center
• Studied nanofiber production and their electrical
  characteristics
• Developed several student activities related to
  nanotechnology, electronics, and research.

tDec Lab Experience
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NanotechnologyElectrical Applications
GOAL Provide a brief overview of the following
topics

• Brief Electronics Overview
• Analog vs. Digital Electronics
• Active vs. Passive Components
• Electrostatics
• Semiconductor Applications
• Electron / Hole Flow Theories
• Diodes and Transistors

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Brief Electronics Overview
Analog vs. Digital

• Analog Circuits
• electronic circuit that operates with currents
  and voltages that vary continuously with time.

• Examples
• Temperature, sound, light, velocity, etc
• To the right is a sine wave (AC Voltage)

http//www.denryo.co.jp/denryo_b/den_b11/den_b11.h
tml
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Brief Electronics Overview
Analog vs. Digital

• Digital Circuits
• function as though currents or voltages exist
  only at one of a set of discrete levels, all
  transitions between levels being ignored.

• Example
• Binary (two-state) digital circuits are the most
  common. The two possible states of a binary
  circuit are represented by the binary digits, or
  bits, 0 and 1. The states are also commonly
  referred to as on and off or high and low

http//www.mitedu.freeserve.co.uk/Circuits/Audio/g
mpre.htm
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Brief Electronics Overview
Active vs. Passive

• Passive Components
• Passive electrical components are those
  components that can only pass, block, or
  attenuate an electrical signal.  (Resistors,
  Capacitors, Coils)
• As passive components, nanofibers can be utilized
  as current carriers (wires).

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Brief Electronics Overview
Active vs. Passive

• Active Components
• Active electrical components are those components
  which have the ability to amplify a signal,
  produce gain, and require a voltage to operate. 
• As active components, nanofibers can be utilized
  for diodes, transistors, integrated circuits and
  other devices.  Their relatively small size makes
  them attractive for next generation electronics
  devices.

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Brief Electronics Overview
Electrostatics Atomic Structure

• an atom is electrically neutral it has the same
  number of protons (positive charges) as it does
  electrons (negative charges)
• objects are charged by adding or removing
  electrons
• a positive charge occurs when there are fewer
  electrons than protons
• a negative charge occurs when there are more
  electrons than protons

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Brief Electronics Overview
Electrostatics Law of Conservation of Electric
Charge

• The net amount of electric charge produced in any
  process is zero. If one region or object acquires
  a positive charge, then an equal amount of
  negative charge will be found in neighboring
  regions or objects.
• Two Methods of Charging and Object
• Conduction a charged object touches another
  object the amount of charge equally divides
  between the two objects the same sign charge is
  acquired by each object
• Induction a charged object is brought near, but
  not touching, another object it attracts charges
  opposite to it and repels charges like it when a
  ground is used, the opposite charge is acquired
  on the other object it is thus charged without
  being touched. Of course, the net charge is still
  zero. Charges have merely been separated.

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Brief Electronics Overview
Coulombs Law

• Coulombs Law describes the electrostatic force
  between two charged objects.
• If the charge is doubled on a charged object,
  the electric force it exerts on another charged
  object is also doubled.
• If the distance between two charged objects was
  allowed to increase, the electric force between
  them decreased with the square of the distance
  between them.

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Brief Electronics Overview
Coulombs Law

• where k is Coulombs constant, or k 9 x 109
  Nm2/C2 (approximate value) or k 8.988 x 109
  Nm2/C2 (actual value)
• q is the magnitude (NO sign) of each charge in
  coulombs
• d is the distance of separation in meters
• F is the electrostatic force in Newtons.

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Nanotechnology Electrostatics
Nanoelectronics Applications

• The electrospinning process uses the principles
  of electrostatics to produce its fine polymer
  jet.
• Through the application of a positive charge on
  the polymer and a negative charge on the plate, a
  difference of charge is created and a balance of
  charge is sought as identified by the law of
  conservation of charges.

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P/N Junction Action DiodeActive Component
Applications
Diode Action Hole Flow vs Electron Flow
A diode is a device that allows current to flow
only in one direction.

• P/N Type Material
• Doping
• TriValent Pentavalent Atoms
• Electron Flow ( to )
• Hole Flow ( to )
• Depletion Zone (Neutral)

• Diode Operation
• Forward Bias
• Reverse Bias
• Nanofiber Application

http//hyperphysics.phy-astr.gsu.edu/hbase/hframe.
html
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P/N Junction Action DiodeActive Component
Applications
Diode Action Forward Reverse Bias
Forward Biased
Reversed Biased
In forward bias, the charge source allows the
introduction of extra electrons into the N-type
material. The depletion zone narrows and current
will flow.
In reverse bias, the charge source is connected
so that the electrons and holes are pulled away
from the neutral zone.
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P/N Junction Action TransistorActive Component
Applications
Transistor Action
Basic Transistor Operation
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P/N Junction Action TransistorActive Component
Applications
Transistor Action - BJT
Below are schematic Diagrams of the two types of
transistors.
A bipolar junction transistor consists of three
regions of doped semiconductors. A small current
in the center or base region can be used to
control a larger current flowing between the end
regions (emitter and collector).
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P/N Junction Action TransistorActive Component
Applications
Transistor Action
Below are two diagrams of a transistor acting as
a switch.
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Nanotransistor