Electronics Lab 20260465

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Electronics Lab20-260-465

• Summer 1999

Welcome!
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Prerequisites

• Measurements Lab
• Electronics I
• Electronics II

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GOALS

• Make interpret measurements
• Recognize equipment limitations
• Verify some device characteristics studied in the
  lecture course
• Learn about some new devices circuits

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METHODOLOGY

• Two people per squad
• Access on your assigned day 800 - 600
• Both partners must be present at all times
• TA help in the afternoon times

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GRADING

• One lab report per squad per week
• 4 quizzes 12 Jul, 26 Jul, 9 Aug, 23 Aug
• Reports count 60
• Quizzes count 40
• Lab work preparedness, orderliness, attitude
  as judged by the TA. This adds or subtracts
  points.

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LABORATORY HELP

• TA Brian Garber
• Instrumentation Specialist John Phillips

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LAB RULES

• Eating or drinking is not permitted in the lab.
  (Neither is smokin, spittin or cussin)
• Keep unused books, backpacks, etc. off the work
  areas. Store them on the wall shelves or under
  the benches.

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LAB RULES

• The last person leaving the room must close the
  door. At night, they must also turn out the
  lights. (Kill-a-Watt !)
• Make certain that all equipment is turned off
  when you leave.

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EQUIPMENT RELATED RULES

• Dont borrow equipment from another lab.
• Dont remove any equipment from Electronics Lab.
• Don't move equipment from one bench to another.
• Don't block vent holes or fans in any equipment.

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EQUIPMENT RELATED RULES

• Use all equipment gently, especially knobs on
  small pieces of equipment.
• Return all resistors and capacitors to their
  proper drawer in the cabinets.
• Report all malfunctioning equipment immediately.

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LABORATORY REPORT

• Cover sheet
• Course Name and Number
• Title of Experiment
• Partners' Names
• Date
• Experiment sheet(s).
• Background theory of the experiment.

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LABORATORY REPORT

• Results Graphs where appropriate, Tables
  where appropriate.
• Data Both measured and calculated, clearly
  labeled.
• Sample calculations.

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LABORATORY REPORT

• Discussion of Results
• The discussion should not be any longer than
  necessary. Punctuation errors, misspelled words
  and poor sentence structure are not acceptable.
• Do not use any report folders. Simply staple the
  report in the upper left corner.

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GRAPHS

• A graph should be given a complete and meaningful
  title showing what it represents and as many of
  the conditions as possible.
• If the title refers to one variable as a function
  of another, it should be ordinate as a function
  of abscissa, not the reverse.

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GRAPHS

• Label axes completely with the names of variables
  and their units or dimensions. Abscissa labels
  should read left to right. Ordinate labels should
  read bottom to top.
• The independent variable should be on the
  abscissa and the dependent variable on the
  ordinate.

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GRAPHS

• Select a convenient and readable scale so that
  interpolation may be made easily and so that the
  graph is spread to a convenient and readable
  extent.

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GRAPHS

• The position of experimental points should be
  shown be some type of symbol. If several curves
  are drawn on the same set of axes, different
  symbols should be used for each curve and each
  curve should be identified in an easily
  understandable manner. If experimental points are
  being compared with a theoretical curve, the
  curve should be so labeled.

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GRAPHS

• Curves are drawn through experimental points in
  most cases to smooth the data and show the
  general law of variation. Use a French curve do
  not draw by hand.
• Horizontal graphs should be put in the report
  with their tops to the inside of the report

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Diodes BJT Transfer Characteristics

• Experiment 1
• http//www.eng.uc.edu/jnevin/Elec_lab/diodes.htm

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Electronics Lab 20-260-465
Diode Characteristics
Where and n is typically between 1 and 2.
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Electronics Lab 20-260-465
Diode Characteristics
Is and n depend on the type of semiconductor
material. In particular, Is varies by orders of
magnitude from one type of semiconductor to
another. Because Is varies, the forward
voltage at any particular current will be quite
a function of semiconductor material. Under
strong forward bias Thus, for a small Is, V
will be larger for a given level of current I.
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Electronics Lab 20-260-465
BJT Transfer Characteristics
Ideally Where IES is an equivalent saturation
current for a BJT.
This transfer characteristic is quite similar
to that of a diode, but with two typical
differences.
1) The ideality factor or emission coefficient,
n, is almost unity for this case.
2) The range of currents over which this holds
is wider than for the case of diodes.
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Electronics Lab 20-260-465
Si Diode Reverse Current
IR for Si, even a power type rectifier, is only a
few nA.
This cant be measured by ordinary lab Digital
Multimeters, even the rather expensive ones.
However, currents in the nA range can be
measured by the novel technique of using an
oscilloscope. Although we think of a scope as
being a voltage input device, it has a finite
input resistance (1 MW) and hence, a finite input
current. Thus, for a given input current, the
resulting terminal voltage is
Expressing I in nA and V in mV, I (nA) V (mV)
For an oscilloscope with a 2 mV/div
sensitivity, this corresponds to a 2 nA/div.
Hence, in effect, the scope becomes an ammeter
with nA sensitivity!
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Diodes BJT Transfer Characteristics

• Experiment 1
• http//www.eng.uc.edu/jnevin/Elec_lab/diodes.htm