Read-out Devices

Moving-Coil System

• connected to the output of the signal processor

• As the signal changes, the pointer deflects

• The amount of deflection is proportional to the signal and thus represents the variable being measured

Plotters definition (2)

• A type of printer used for drawing or creating large-scale images, diagrams, and graphics

• Often uses a moving-coil system to control the movement of the pointer (pen, inkjet nozzle, or heated stylus) for precise drawing or printing

Plotters types (2)

• Ink-jet plotters

• Thermal plotters

Ink-jet plotters

Uses capillary action with a ‘pointer’ and ink pump to spray ink onto the paper

Thermal plotters

Uses a heated pointer to transfer heat onto heat-sensitive paper, creating marks without ink

7 Segment Digital Display Systems based on (2)

LED (Light Emitting Diode) or LCD (Liquid Crystal Display) based

Advantages of 7 Segment Digital Display Systems

• Direct readout

• LCD displays

Direct readout

The numbers are clearly displayed, allowing immediate reading of the values - even in low-light situations

LCD displays

Use liquid crystals that respond to electrical currents, typically requiring backlighting for visibility, but are energy-efficient

Monitors types (2)

• CRT (Cathode Ray Tube)

• LCD-TFT (Flat Screen)

CRT general (3)

• Uses a cathode ray tube to display images by shooting electron beams at phosphorescent screens

  • producing light to form the image

• Older technology, typically bulkier and less energy-efficient

CRT electrobeam

responsible for exciting phosphors on the screen, producing the light that creates the image

LCD-TFT general (6)

• LCD (Liquid Crystal Display):

  • uses liquid crystals that are manipulated by electrical currents to display images

• TFT (Thin Film Transistor):

  • a type of LCD that uses a thin film of transistors to improve the display quality

  • provides sharper images and better color contrast

• Common in flat-screen monitors due to its slim design and energy efficiency.

LCD how it works? (3)

• The liquid crystals are manipulated by electrical currents to control light passing through them

• When an electric field is applied, the liquid crystals align in a way that either blocks or allows light to pass through

  • creating images or text on the screen

Footprint for CRT vs LCD-TFT (outlied is preffered)

• CRT: larger, bulky, thick

• LCD-TFT: smaller, slim/flat

Image brightness for CRT vs LCD-TFT

• CRT: higher brightness

• LCD-TFT: lower brightness

Colour for CRT vs LCD-TFT

• CRT: rich, natural colours

• LCD-TFT: not that colourful + not vibrant

  • bc/ of crystals

Size - weight for CRT vs LCD-TFT

• CRT: large, heavy

• LCD-TFT: slim, lightweight

Screen burn-in for CRT vs LCD-TFT

• CRT: prone to it

• LCD-TFT: Minimal

“ghost”/ lining of image on screen

Viewing angle for CRT vs LCD-TFT

• CRT: any direction

• LCD-TFT: straight on - 1D

Response time for CRT vs LCD-TFT

• CRT: ultra-fast

• LCD-TFT: slower

Screen-flicker for CRT vs LCD-TFT

• CRT:prone to flicker

  • refreshed by the electron beam scanning the screen at a certain refresh rate - slow rate

• LCD-TFT: flicker-free viewing

  • image remains stable

Magnetic interference for CRT vs LCD-TFT

• CRT: prone to magnetic interference

  • bc/ electron beam can be distorted by external magnetic fields

    • leading to image or color distortions

• LCD-TFT: immune

  • not rely on electrobeams

Power consumption for CRT vs LCD-TFT

• CRT: High

• LCD-TFT: Low - energy efficient

Dead-pixels for CRT vs LCD-TFT

• CRT: none

• LCD-TFT: crystals show black spots

Contrast for CRT vs LCD-TFT

• CRT: Excellent black&white

• LCD-TFT: lower contrast

Medical Printers types (4)

• ink-jet

• colour laser

• thermal sublimation

• video printers