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I'm not able to obtain an adapter from local markets for vga to composite video output. Found a circuit [VGA to composite circuit. Does it work?] enter image description herethat claims to work. I didn't had a vga cable so I inserted jumpers into the port and created the circuit in breadboard then to rca composite cable. I found flickering screen when connected to tv but not a greyscale output of my screen, it doesn't detect source.

Why didn't it work? Is it because I must use vga cable instead of jumpers? How to make it work? I also found active adapters that takes external power source.[https://www.amazon.com/StarTech-com-Resolution-Composite-S-Video-Converter/dp/B001NXDQEK] enter image description hereDo I need one of them?

(I have an old crt samsung tv that has video, audio & rf input ports only that I want to use as a external display for my laptop whose lcd screen is damaged.)

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  • \$\begingroup\$ It is very likely that your laptop cannot produce the correct video format for the TV. \$\endgroup\$
    – Dave Tweed
    Apr 12, 2020 at 13:10

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No, in general a simple passive cable does not work. You'd have to use some kind of tool to force the VGA output to generate a compatible 15kHz signal. Even if you can manage that, the picture will have low resolution and it will be black and white. You would need an active converter.

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  • \$\begingroup\$ Yeah, I tried stupid stuffs. Thanks! \$\endgroup\$ Apr 12, 2020 at 14:05
  • \$\begingroup\$ Does using jumpers into port works if I don't have vga cable? Or is their any circuit inside vga cable that makes it detectable to computer? \$\endgroup\$ Apr 12, 2020 at 14:22
  • \$\begingroup\$ I don't know what jumpers you mean. VGA signals are high speed analog signals that are carried via 75 ohm coaxial cable. Any random piece of wire just can't handle the bandwidth. Cables do not contain circuitry to detect it is connected, that will be on the monitor side. \$\endgroup\$
    – Justme
    Apr 12, 2020 at 14:43

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