• Vinny_93@lemmy.world
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    2 days ago

    What did dude think was coming out of the VGA port? Tiny photographs? It’s all electricity through wires, of course it’ll send some electricity into a phone

    • Sundray@lemmus.org
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      2 days ago

      It’s sending out the pixels, silly! A stream of little pixels in neat little rows.

    • TimeNaan@lemmy.world
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      2 days ago

      Yeah but is the voltage correct? It should be 5V to charge a phone over USB, is that part of the VGA spec?

      • zurohki@aussie.zone
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        2 days ago

        With USB power delivery, you can get 9V, 12V or higher over USB. Usually the device requests higher voltage from a PD charger, but it’s not impossible for a modern device to be able to cope with just having 12V shoved into it.

        • FishFace@lemmy.world
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          2 days ago

          The USB device would have been made wrong if it just shoved 12V down the power lines without negotiating it.

          • zurohki@aussie.zone
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            9 hours ago

            That’s probably only true for USB power supplies - a USB adapter isn’t set up to do anything with voltage and probably just passes the positive and negative pins through.

            The VGA adapter feeding power back through USB in the first place, yeah, that’s not supposed to happen.

            • FishFace@lemmy.world
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              7 hours ago

              Put it this way, either the standard on the other end of the adapter specifies 5V, or the adapter doesn’t just pass it through, or the adapter is broken!

      • Anivia@feddit.org
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        2 days ago

        Doesn’t matter. The VGA to HDMI adapter is active, not passive, so it matters if HDMI has a 5v rail, not VGA

        • Fluffy_Ruffs@lemmy.world
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          2 days ago

          If, hypothetically, VGA didn’t have a 5v rail then how would power get from the monitor to the HDMI adapter. It would absolutely have to be a part of the spec.

          • knight_alva@lemmy.world
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            2 days ago

            If the vga/hdmi adapter is active then this abomination could actually pass display information provided you had a micro-usb device that supported display out over usb (idk if there is such a thing and if so it probably doesn’t work all that well but still)

          • Anivia@feddit.org
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            2 days ago

            It doesn’t need to be 5v. An active adapter can have a buck converter.

            In reality active HDMI adapters get powered by the HDMI device though, not the VGA monitor, so it’s a moot point anyways

      • 9point6@lemmy.world
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        2 days ago

        Yeah I don’t think there’s a 5V pin for VGA.

        I think if we had the scenario where we had a higher voltage than needed, we could have a toasty voltage regulator making something happen, but going the other way would need boost circuitry unlikely to exist in these parts, in my understanding

    • SkyezOpen@lemmy.world
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      2 days ago

      I don’t know shit about cables but it’s plugged into a monitor. My intuition is that a monitor shouldn’t be pushing power out through a video input port.

      • pivot_root@lemmy.world
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        2 days ago

        DisplayPort has a +3.3V 500mA pin specifically for pushing power. In theory, great for powering an active adapter. In practice, has killed motherboards because Dell can’t design a computer for shit.

        • boonhet@sopuli.xyz
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          2 days ago

          Friendly reminder that if you use a Dell charger on a HP, nothing happens but vice versa, you damage the motherboard. It kills a chip used for charging. Dell used the same size barrel jack, but they wired it differently from everyone.

      • VindictiveJudge@lemmy.world
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        2 days ago

        The monitor has to send some data to the computer to tell it what screen resolutions it accepts. VGA, HDMI, and DisplayPort will all do that for sure. Less certain about component, composite, and S-Video.

      • zurohki@aussie.zone
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        2 days ago

        Signals aren’t magic, they consist of electrical power. You can get at least a little bit of power from anything that isn’t an optical port.

        • Ferk@programming.dev
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          2 days ago

          Technically, even an optical port can deliver power. Light is just a particular form of electromagnetic wave that just happens to use another method of transmission (and you might need a different mechanism to transform its energy), but it also has an intensity, potential energy and resistance in the medium of propagation.

        • TheOakTree@lemmy.zip
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          2 days ago

          Maybe somewhere in the chain, the 5V from pin 9 is being converted to 5V shared across power and the video signal. So even if this chain worked in carrying a video signal it could be very weak or distorted.

          Purely a guess though.