UNIT IV

STORAGE AND DISPLAY

DEVICES

U.NAGABALAN ., AP / EEE

M.VENKATESWARAN., AP / EEE

R.VANITHA., AP / EEE

RMD ENGINEERING COLLEGE

TOPICS

• MAGNETIC DISK AND TAPE – RECORDERS

• DIGITAL PLOTTERS

• PRINTERS

• CRT DISPLAY

• DIGITAL CRO

• LED

• LCD

• DOT MATRIX DISPLAY

• DATA LOGGERS

2

RECORDERS

•A recorder is a measuring instrument which records time varying quantity, even

after the quantity or variable to be measured has stopped.

•The electrical quantities such as voltage & current are measured directly.

•The non- electrical quantities are recorded using indirect methods.

•The non- electrical quantities are first converted to their equivalent voltages or

currents, using various transducers.

Electronic recorders may be classified as:

1.Analog recorders

2.Digital recorders

Analog recorders dealing with analog systems can be classified as

•Graphic recorders

•Oscillographic recorders

•Magnetic Tape recorders

Digital recorders dealing with digital output can be classified as

•Incremental digital recorders

•Synchronous digital recorders

MAGNETIC TAPE RECORDER

Basic Components of Tape Recorder

1.Recording Head

2.Magnetic Tape

3.Reproducing Head

4.Tape Transport Mechanism

5.Conditioning Devices

MAGNETIC TAPE RECORDER

TAPE TRANSPORT MECHANISM

PRINTERSIMPACT PRINTERS press formed character faces against an inked ribbon onto the paper.

▪ line printer

▪ dot matrix printer.

NON IMPACT PRINTER and plotters use laser techniques, inkjet sprays, xerographic processes, electrostatic methods and e1ectrothermal methods to get images onto the paper.

• A ink-jet printer

• laser printer

DRUM PRINTERS

DOT MATRIX PRINTERS

LASER PRINTER

DIGITAL PLOTTERS

CRT DISPLAY

DIGITAL CRO

What is an LED?

• Light-emitting diode

• Semiconductor

• Has polarity

LED: How It Works

• When current flows across a diode

• Negative electrons move one way and positive holes move the other way

LED: How It Works

• The wholes exist at a lower energy level than the free electrons

• Therefore when a free electrons falls it losses energy

LED: How It Works

• This energy is emitted in a form of a photon, which causes light

• The color of the light is determined by the fall of the electron and hence energy level of the photon

Inside a Light Emitting Diode

1. Transparent Plastic Case

2. Terminal Pins

3. Diode

Kinds of LEDs

How to Connect a LED:

• Requires 1.5~2.5V and 10 mA

• To prevent overloading, use resistor 470 Ω

https://www.elprocus.com/light-emitting-diode-led-working-application/

LIQUID CRYSTAL DISPLAY (LCD)