This document discusses various storage and display devices used in instrumentation systems. It describes different types of recorders like analog recorders, digital recorders, and oscillographic recorders that are used to record electrical and non-electrical quantities over time. Magnetic tape and disc recorders, which use magnetic media to store data, are also covered. The document also outlines different types of printers like impact, non-impact, inkjet and laser printers. Additionally, it provides details about CRT displays, LEDs, LCDs and dot matrix displays that are commonly used in instrumentation.

1. STORAGE AND DISPLAY
DEVICES
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Contents:
Magnetic disk and tape
Recorders
digital plotters
Printers
CRT display
 digital CRO
 LED
 LCD
dot matrix display.

2. Recorders
 A recorders records electrical and non electrical quantities as
a function of time.
 They are used for having permanent records. It monitors
continuously the condition state or value of the process
variable such as flow, force, pressure, temperature, current ,
voltage, electrical power etc.
 Current and voltage can be recorded directly while the non
electrical quantities are recorded indirectly by first converting
them to equivalent currents or voltages with the help of
sensors or transducers.
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3. Kongunadu College of Engineering and Technology
Recording device
Analog recorders Digital recorders
Incremental digital Synchronous digitalOscillographic recorders Magnetic tape recorders
Graphic recorders
Strip Chart recorders
X-Y recorders
Circular Chart recorders
Galvanometer type
Null type
LVDT recorders
Potentiometric recorders Bridge recorders

4. Magnetic Tape and Disc Recorders
 Magnetic tapes and magnetic discs are essentially storage
devices. A magnetic tape is a thin dimensionally stable plastic
coated with iron oxide particles one side.
 Mechanism-The magnetic tapes or disc passes under the gap,
and the oxide particles retain a state of permanent
magnetization proportional to the flux existing at that instant ,
the particle leaves the gap.
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5. Basic Components of Tape recorder
 Recording Head
 Magnetic Head
 Reproducing Head
 Tape transport mechanism
 Conditioning device.
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6. Methods Of Magnetic Tape
recording
 Direct Recording
 FM recording
 Pulse Duration Modulation Recording
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7. Printers
Classification
Impact printers
Non Impact Printers.
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8. Impact printers
1. Line Printer
2. Drum Printer.
3. Chain Printer.
4. Dot Matrix Printer
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9. Kongunadu College of Engineering and Technology

10. Non Impact Printers.
 Ink jet Printer
 Laser Printer
 Thermal Transfer Printer
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11. Cathode Ray Oscilloscope (CRO)
 The cathode ray oscilloscope is a versatile laboratory
instrument used for display, measurement and analysis of
waveform.
 CRO are very fast X-Y plotter displaying an input signal
versus another signal or versus time.
 The Stylus of this plotter is a luminous spot which moves
over the display area in response to an input voltage.
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12. Kongunadu College of Engineering and Technology

13. Kongunadu College of Engineering and Technology

14. Cont…
 The luminous spot is produced by a beam of electrons striking
a fluorescent screen.
 Applications of CRO
 Sampling oscilloscopes.
 Storage oscilloscopes.
 An analog oscilloscope.
 Cathode ray tube (CRT)
 Electron gun assembly.
 Deflection plate assembly.
 Fluorescent screen.
 Glass envelope.
 Base through which connection are made to various parts.
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15. LED
 It is perhaps the most important of the display device for use in
instrumentation systems.
 It is a PN junction device that emits light when a current passes
through it in the forward direction.
 Charge carrier recombination occurs at PN junction as
electrons from N side recombines with holes on P side.
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16. Cont…
 When this happens ,charge carrier give up energy in the form
of heat and light.
 If the semiconductor material is translucent the light is
emitted and junction is source of light.
 Charge carrier recombination takes place in the P type
material. For maximum light emission a metal film anode is
deposited around edge of P Type material.
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17. LCD
 Used in application of display of numeric and alpha numeric
characters in dot matrix and segmental displays.
 Types
 Dynamic scattering type
 Field effect type.
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18. Dot Matrices
 3x5 dot matrix
 Dot matrix utilizing 27 Dots
 5x7 dot matrix
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19. Kongunadu College of Engineering and Technology