What is the vacuum fluorescent display ( VFD ) ?
It is a kind of display which used to give bright output than LCD.It can be displayed seven segments numerals and also alpha numericals as shown in figure. This technology was replaced by Light Emitting Diode (LED) but still used in some equipment which need bright display.
VFD Operating Principles
The VFD is a kind of triode vacuum tube with three electrodes which are:
1. Cathode Filament(s)
2. Control Grids
3. Illumination Anodes
The electrons emitted from the cathode filaments are controlled by the grids. When the grid is supplied with a positive voltage, it attracts the negative electrons, diffuses them and, due to their acceleration, many flow through the grid mesh towards the anode (opposite charges attract). However, when the grid is supplied with a negative voltage, it repels the negative electrons and prevents them from reaching the anode (similar charges repel).
The illuminating anodes are coated with phosphor which emits light when hit by the electrons. Each anode forms a segment or dot, which collectively form individual characters. When an anode is supplied with a positive voltage, it will attract the electrons which have been accelerated through the grid. The segment emits light when these electrons impact on the phosphor coating. Alternatively when anodes are supplied with a negative voltage, they will repel electrons from their phosphor coating and therefore will not illuminated.
Liquid Crystal Display (LCD)
It is a another very popular display not only alpha numeric but also in advanced applications like TV, Computer monitors.Hear I'm describing only which use in electronic equipments applications as bellow.
Pin Configuration
Under normal operation following voltages must be shown.
pin 1,2===> 5V,
pin 15,16 ===> 5V, this is for LCD back light
It is a kind of display which used to give bright output than LCD.It can be displayed seven segments numerals and also alpha numericals as shown in figure. This technology was replaced by Light Emitting Diode (LED) but still used in some equipment which need bright display.
VFD Operating Principles
The VFD is a kind of triode vacuum tube with three electrodes which are:1. Cathode Filament(s)
2. Control Grids
3. Illumination Anodes
The electrons emitted from the cathode filaments are controlled by the grids. When the grid is supplied with a positive voltage, it attracts the negative electrons, diffuses them and, due to their acceleration, many flow through the grid mesh towards the anode (opposite charges attract). However, when the grid is supplied with a negative voltage, it repels the negative electrons and prevents them from reaching the anode (similar charges repel).
The illuminating anodes are coated with phosphor which emits light when hit by the electrons. Each anode forms a segment or dot, which collectively form individual characters. When an anode is supplied with a positive voltage, it will attract the electrons which have been accelerated through the grid. The segment emits light when these electrons impact on the phosphor coating. Alternatively when anodes are supplied with a negative voltage, they will repel electrons from their phosphor coating and therefore will not illuminated.
Liquid Crystal Display (LCD)
It is a another very popular display not only alpha numeric but also in advanced applications like TV, Computer monitors.Hear I'm describing only which use in electronic equipments applications as bellow.
Pin Configuration
Under normal operation following voltages must be shown.
pin 1,2===> 5V,
pin 15,16 ===> 5V, this is for LCD back light
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