Category: Indicators and Display Devices


Printers: Character printers and graphic plotters are the two devices used to prepare a permanent (or hard copy) record of computer output. The basic difference between printers and plotters is that the former are de­vices whose purpose is to print letters, numbers and similar characters in text-readable form, while the latter print diagrams with continuous […]

Liquid Vapour Display

Liquid Vapour Display(LVD): Liquid Vapour Display are the latest in economical display technology. They employ a new reflective passive display principle and depend on the presence of ambient lights for their operation. Figure 2.25 gives the structure of a typical LVD cell. It consists of a transparent volatile liquid encased between two glass plates and side spacers. […]

Electrophoretic Image Display

Electrophoretic Image Display (EPID): Electrophoretic Image Display is the movement of charged pigment particles suspended in a liquid under the influence of an electric field. This pheonomenon has been uti­lised in electrophoretic image displays, as shown in Fig. 2.24. The basic principle; fabrication and operating characteristics of a reflective type Electrophoretic Image Display (EPID) panel […]

Incandescent Display

Incandescent Display: Incandescent Display has been a basic process of light generation for several decades. This process is now down in fully integrated electronic displays. Incandescent display using 16 segment as well as 5 x 7 dot matrix formats fabricated using thin film micro electronics are now available for alphanumeric characters. Such displays are characterized […]

Dot Matrix Displays

Dot Matrix Displays: Excellent alphanumeric characters can be displayed by using dot matrix LEDs with an LED at each dot location. Commonly used Dot Matrix Displays of prominent characters are 5 x 7, 5 x 8, and 7 x 9, of which 5 x 7 shown in Fig. 2.20 (a), is very popular due to […]

Segmental Displays using LEDs

Segmental Displays using LEDs: In Segmental Displays using LEDs, it is usual to employ a single LED for each segment. For conventional 7 segment LED displays (including the decimal point, i.e. the 8th segment), the wiring pattern is simplified by making one terminal common to all LEDs and other terminals corresponding to different segments. The […]

Segmented Gas Discharge Displays

Segmented Gas Discharge Displays: Segmented Gas Discharge Displays work on the principle of gas discharge glow, similar to the case of Nixie tubes. They are mostly available in 7 segment or 14 segment form, to display numeric and alphanumeric characters. Since these devices require high voltages, special ICs are developed to drive them. The construction […]

Gas Discharge Plasma Displays

Gas Discharge Plasma Displays: Gas Discharge Plasma Displays – These are the most well-known type of alphanumeric displays. Their operation is based on the emission of light in a cold cathode gas filled tube under break­down condition. These cold cathode numerical indicators are called Nixies (Numicators and Numbertrons). This Nixie tube is a numeric indi­cator […]

Liquid Crystal Display(LCD)

Liquid Crystal Display(LCD): Liquid Crystal Display(LCD) are passive displays characterised by very low power consumption and good contrast ratio. They have the following characteristics in common. They are light scattering. They can operate in a reflective or transmissive configuration. They do not actively generate light and depend for their operation on ambient or back lighting. […]

Light Emitting Diodes(LED)

Light Emitting Diodes(LED): The Light Emitting Diodes, Fig. 2.10 (a) is basically a semiconductor PN junction diode capable of emitting electromagnetic radiation under forward conductions. The radiation emitted by LEDs can be either in the visible spectrum or in the infrared region, depending on the type of the semiconductor material used. Generally, infra-red emitting LED’s […]