1 - The digital signals from the operational environment or program is
received by the VGA card (sometimes built into the motherboard
PC).
The board passes the signals through a circuit known as a digital-analog converter (DAC).
Typically, the
circuit is in particular a chip that has actually three DACs - one for each of the three primary colors
used by a monitor: red, blue and green.
2 - The DAC circuitry compares the digital values sent by the PC with a table containing the verificagäo degrees
voltage (voltage) that match the three primary colors needed to create the color of a single pixel.
The table contains
values for 262,144 possible colors, of which 256 can be armazendas in memory of the VGA card.
(Super VGA monitors,
which have more memory may manage greater number of colors and higher resolutions, the more pixels).
3 - The board sends the signal electrons of three triggers, located at the rear of the cathode ray tube (CRT)
monitor.
Each electron trigger sends an electron beam, each beam goes to one of the three primary colors.
The
intensity of each beam is controlled by the signals of the plate.
4 - The board also sends signals to the mechanism that is in the neck of the CRT that focuses and directs the electron beam.
Part of the mechanism, a deflection coil (magnetic deflection yoke), uses magnetic fields to deflect the direction of
electron beams.
The signals sent to the deflection coil help set the display resolution - the number of pixels
vertical and horizontal - and vertical scan rate (refresh rate) Monitor, which is the frequency with which the image of
screen will be redrawn.
5 - beams pass through the holes of a flat metal known as shadow mask.
The purpose
this mask is to keep the electron beams correctly aligned in relation to their targets within the screen of the tube.
The dot
pitch of the CRT is the measure of how close the orifices are each other, the closer they are, the smaller the dot pitch.
This, in turn, generates a more accurate picture.
The holes in the majority of shadow masks are arranged
triangularly, with the important exception of the Sony Trinitron tube, used by several manufacturers of monitors.
The holes in Trinitron are arranged in parallel slots.
6 - The electrons hit the phosphors coating the inside of the screen.
(Matches are materials that glow when hit
by electrons). fóstro Three different materials are used - one for red, one for blue and one for
green.
The stronger the electron beam reaches the match, the more light it will emit.
If each point red, green and
blue composition is reached with equal intensity by the electron beam, the result will be a point of white light.
To create different colors, the intensity of each beam is varied.
After a spot beam leaves a match,
This still continues to shine for a time, a phenomenon called persistence.
For the image to remain
stable matches must be reactivated by repeated scans of electron beams.
7 - Once the beams perform a horizontal sweep across the screen, the electron beam is turned off while the
triggers electron beams deviate to the left end of the screen, at the point just below the scan line
earlier.
This process is known as horizontal scan tracking.
8 - deflection coil continuously changes the angles of curvature of electron beams so that they sweep across
the surface of the screen, from top left to bottom right edge.
This full scan of
screen is known as a field.
After completing a field, the beams return to the upper left corner to
start a new field.
The screen is usually reconstructed or redesigned, about 60 times per second.
9 - Some video cards sweep line but not in the online field, a process known as entanglement.
Interlacing
allows the card to generate higher resolution - ie, more sweeping lines - with cheaper components.
However, the decrease in
intensity of matches between each pass is more visible, making the screen flicker (flicker).
Source: Evolution of Computers
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