1. Digital Displays Cathode Ray Tubes Flat Panel Displays
Lecture 8: Displays
Digital Displays
Cathode Ray Tubes
Flat Panel Displays
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2. Summary of What We Have Learned
Ohm’s Law
Resistor Combinations
What a Diode Does
Transistors as Switches
Op-Amp Configurations
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3. Introduction to Engineering Electronics
Ohm’s Law
Kirchoff’s Voltage Law
Kirchoff’s Current Law
Series Equivalent
Parallel Equivalent
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4. Diode V-I Characteristic
For ideal diode, current flows only one way
Real diode is close to ideal
Ideal Diode
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5. Introduction to Engineering Electronics
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6. Introduction to Engineering Electronics
Op-Amp
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7. Ideal Op-Amp Continued
Bandwidth is also infinite. Thus, an ideal op-amp works the same at all frequencies.
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8. Golden Rules for Op-Amps
The output attempts to do whatever is necessary to make the voltage difference between the two inputs zero. (Negative Feedback is Required)
The inputs draw no current.
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9. Op-Amp Configurations
Buffer or Voltage Follower
No voltage difference between the output and the input
Draws no current, so it puts no load on the source
Used to isolate sources from loads
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10. Op-Amp Configurations
Non-Inverting Amplifier
Note that this formula is different in the lab write up
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11. Op-Amp Configurations
Inverting Op-Amp
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12. Introduction to Engineering Electronics
Binary Numbers
0 0000
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001 =
Introduction to Engineering Electronics
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13. Astable and Monostable Multivibrators
What are they good for?
Astable: clock, timing signal
Monostable: a clean pulse of the correct height and duration for digital system
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14. Introduction to Engineering Electronics
555 Timer
The correct frequency is given by
Note the error in the figure
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15. From What We Have Seen So Far, How Would We Make a Display?
LEDs in some kind of an array
How to arrange them?
How to control them?
What is the purpose of the display?
How much should it cost?
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16. Introduction to Engineering Electronics
Binary Numbers
0 0000
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001 =
Introduction to Engineering Electronics
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17. Introduction to Engineering Electronics
7 Segment Displays
Binary inputs are converted to a decimal number display by turning on a set of 7 LEDs
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18. Introduction to Engineering Electronics
7 Segment Displays
Common cathode at the right and common anode at the left
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19. Introduction to Engineering Electronics
7 Segment Displays
This is the 0-9 counting circuit you will be building in the lab.
Note that it has to count and then convert the binary to show decimal
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20. Displays Applications
7 Segments are excellent for displaying simple alphanumeric information – multimeters, clocks, etc.
More complex displays are needed to show images – computer displays, televisions, etc.
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21. 2 Minute Quiz Name_______Sec______Date______
Give three examples of electronic displays
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22. Dividing Images Into Pixels
Second image is blown up many times to show the individual pixels
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23. Dividing Images Into Pixels
The second image is blown up a bit less but pixels are still obvious
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24. Dividing Images Into Pixels
The second image is sampled more coarsely
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25. Dividing Images Into Pixels
Black and white or single color displays are easier to implement
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26. Dividing Images Into Pixels
Images can be constructed by scanning across them, line-by-line
The original image is encoded in this manner (e.g. this is the way a scanner or copier works) by, say, starting at the upper left and going line by line to the lower right
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27. Introduction to Engineering Electronics
Plasma Displays
Large, bright, flat panel display
View from a wide angular range
Designed for HDTV
Available from many companies
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28. Introduction to Engineering Electronics
Plasma Displays
High voltage discharge creates high energy photons (UV) that excite phosphors
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29. Introduction to Engineering Electronics
Plasma Displays
Note the patterns of the address and display electrodes
To excite an address, both voltages must be applied
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30. Introduction to Engineering Electronics
Plasma Displays
Fujitsu ALIS display
More complex electrodes but better use of surface area for display
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31. Introduction to Engineering Electronics
Plasma Displays
Discharge region geometry and voltages
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32. 2 Minute Quiz Name_______Sec_____Date_______
What is a pixel?
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33. Introduction to Engineering Electronics
Displays: CRT
In a CRT, an electron beam excites the phosphor rather than a UV photon
The beam is directed to a spot on the surface using sweep plates
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34. Introduction to Engineering Electronics
Displays: CRT
Three separate electron guns are required to produce a color picture
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35. Introduction to Engineering Electronics
Displays: CRT
At the left is the layout of the mask and phosphors
At the right is the scanning sequence
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36. Introduction to Engineering Electronics
Displays: CRT
A large variety of configurations are used by manufacturers
Look carefully at the screen of your TV
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37. 2 Minute Quiz Name_______Sec______Date______
True or False
Blue light is higher energy than red light
Most colored light is not produced directly
Solid state light is generally produced directly
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38. Introduction to Engineering Electronics
Image From My TV
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39. Same Image Enlarged to Show Screen
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40. Same Image Enlarged Further
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41. Same Image Enlarged Further
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42. Unsmoothed Image Enlarged Further
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43. Introduction to Engineering Electronics
Displays: Early TV
Allen Dumont
B.S.E.E. RPI 1924
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44. Introduction to Engineering Electronics
Displays: Dumont
Developed the first practical CRT (previous versions lasted only 10s of hours)
First company to market home TV receiver in 1938 (previous slide)
Dumont network until 1956 – It could not compete with radio networks (poorly funded)
Broadcast Jackie Gleason, first sporting events, but shows were bought by big 3 networks
Dumont was one of broadcastings first millionaires
Introduction to Engineering Electronics
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45. Where Will You See This Material Again?
7 Segment Displays: Many courses
CRT: ECSE-2100 Fields and Waves I
Digital Imaging: ECSE-4540 Voice and Image Processing
RF Circuitry: ECSE-4060 Communications Circuits
Plasmas: ECSE-4320 Plasma Engineering
Optics: ECSE-4630 Lasers and Optical Engineering and ECSE-4640 Optical Communications and Integrated Optics
Introduction to Engineering Electronics
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46. Introduction to Engineering Electronics
Imaging Tools
Mathworks Image Processing Toolboxes
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47. Introduction to Engineering Electronics
2 Minute Quiz ANSWERS
Electronic displays-7 segment, plasma, CRT
A pixel is a PIcture Element, smallest unit of a display grid
True or False
Blue light is higher energy than red light TRUE
Most colored light is not produced directly TRUE, reflected
Solid state light is generally produced directly TRUE
Introduction to Engineering Electronics
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11/9/2018

48. Charged Particle Accelerators
Fermilab
Medical Accelerator
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