VGA to TV or Composite video output

[gurjeet_saini]

CAN ANY ONE PROVIDE ME SIMPLE CIRCUIT (WITHOUT IC) TO CONVERT VGA OUTPUT (FROM PC) TO TV/COMPOSITE VIDEO .....
ACTUALLY I WANT TO USE MY T.V AS MONITOR/LCD WITH MY PC :wink: :razz:

 

[betwixt]

re: VGA to TV or COMPOSITE VIDEO OUTPUT

It might be posible to do it of the resolution is only 640x480 pixels and you are prepared to see it without color. For any other resolution or in color you need a scan converter which will iinvolve at least one IC and some memory. It would be cheaper to buy one than make one.

Brian.

 

[davoud]

re: VGA to TV or COMPOSITE VIDEO OUTPUT

If your graphic card don't have a video out, you can make it by AD722

 

[Audioguru]

re: VGA to TV or COMPOSITE VIDEO OUTPUT

I guess India still uses old analog TV (ours is high-definition digital today). Is it NTSC or PAL or Seq... (the French system)?

 

[betwixt]

re: VGA to TV or COMPOSITE VIDEO OUTPUT

The old French system is SECAM but almost all European countries now use HD or SD digital systems.

That circuit will only work if the horizontal and vertical scan rates at the VGA output are the same as the analog TV standard, that's why I said it would be 640 x 480 pixels, it's only the base VGA definition that uses compatible rates. It is possible to use nothing more than a resistor network to get composite video (subject to the scan rate) but to get color the modulator IC is needed as shown.

Brian.

 

[gurjeet_saini]

re: VGA to TV or COMPOSITE VIDEO OUTPUT

It might be posible to do it of the resolution is only 640x480 pixels and you are prepared to see it without color. For any other resolution or in color you need a scan converter which will iinvolve at least one IC and some memory. It would be cheaper to buy one than make one.

Brian.

RGB colrs does nt matter for me . If black & white is possible then pls provide me the circuit . .

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I guess India still uses old analog TV (ours is high-definition digital today). Is it NTSC or PAL or Seq... (the French system)?

lol
I have sony LCD HDMI .
I need this just for fun and hobby purpose
it has ntsc and pal both in tv

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The old French system is SECAM but almost all European countries now use HD or SD digital systems.

That circuit will only work if the horizontal and vertical scan rates at the VGA output are the same as the analog TV standard, that's why I said it would be 640 x 480 pixels, it's only the base VGA definition that uses compatible rates. It is possible to use nothing more than a resistor network to get composite video (subject to the scan rate) but to get color the modulator IC is needed as shown.

Brian.

thats great bro ,,, no need of colors ,, i am happy with black & white picture..
so please give me the circuit to get composite video.... and i think i need a driver software also in pc (i have this)

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ALL EXPERTS PLEASE TELL ME IS THIS CIRCUIT WILL REALY WORK OR NOT ?????????????

 

[betwixt]

re: VGA to TV or COMPOSITE VIDEO OUTPUT

I think that's the simple resistor circuit I used before but I had it as a schematic rather than a layout. All it does is sum together the Red, Green and Blue signals in the correct proportions and 'sits' them on a pedestal made from the sync pulses. Please note it requires a standard 75 Ohm video load (normally inside the TV) and if you look at it without the load conected it will be completely wrong.

I stress again, you must use the lowest VGA resolution of 640x480 pixels, it will not work at higher resolutions because the sync speeds and polarities will be wrong.

Brian.

 

[gurjeet_saini]

re: VGA to TV or COMPOSITE VIDEO OUTPUT

I think that's the simple resistor circuit I used before but I had it as a schematic rather than a layout. All it does is sum together the Red, Green and Blue signals in the correct proportions and 'sits' them on a pedestal made from the sync pulses. Please note it requires a standard 75 Ohm video load (normally inside the TV) and if you look at it without the load conected it will be completely wrong.

I stress again, you must use the lowest VGA resolution of 640x480 pixels, it will not work at higher resolutions because the sync speeds and polarities will be wrong.

Brian.

thanks for your great reply
do you have any schemetic (temporarely) , because i am beginer yet
i think this circuit will work, as its cleared on source webpage of schemetic
load means i have to add resistor on output
your suggetion is good to keep resolution low