I have a laptop with an HDMI port and I want to use my old monitor which has VGA port. Do I need HDMI-to-VGA or VGA-to-HDMI adapter?

Question

• I have an old monitor that only has a VGA port.

• I have a new Dell laptop that only has an HDMI port.

I want to use that old monitor with my new laptop.

Do I need a HDMI-to-VGA adapter or VGA-to-HDMI adapter? My common sense would tell a VGA-to-HDMI adapter, but I am not 100% sure.

I have seen some people in online forums talking about active and passive connectors. It is turning me crazy. I can't really grasp that. In layman's terms, what should I be using?

Solution 1

You need a HDMI-to-VGA adapter. Your laptop is outputting an HDMI signal which has to be converted to VGA.

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Some connectors are physically different, but use identical signaling - in these cases a passive adapter is sufficient. Passive means there's no signal transformation necessary. It's just two different connectors wired together. For example, DVI-A is just repackaged VGA (aka D-Sub) and they can be passively adapted both ways. Similarly HDMI uses the same signaling as DVI-D, so you can convert between them without any electronics - just wires.

HDMI and VGA are completely incompatible, so you need an active adapter which will decode the HDMI signal and produce equivalent VGA signal.

You may be tempted to use a passive HDMI→DVI adapter and then a passive DVI→VGA adapter, but this won't work. HDMI would be converted into DVI-D, and the second adapter needs DVI-A input. DVI-D and DVI-A use physically compatible connectors, but the signal won't go through.

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Note that while active adapters are directional (HDMI→VGA is completely different than VGA→HDMI), passive adapters are usually not. As long as passive adapter's plugs physically fit, it will work in both directions. So for example a HDMI→DVI adapter would work for DVI→HDMI too.

Solution 2

Many people get this the wrong way round.

Signals go from > to

You might think you're connecting your display to your computer, but you're not. You're connecting the computer to the display.

This means your signal goes from the computer to the display - that's an HDMI to VGA connection.

HDMI is a digital format, VGA is an analog format, so any connector you get must be an active connector.

Solution 3

I'll go through your Q point by point.

Do I need (hdmi to vga adapter) OR (vga to hdmi adapter)? My common sense would tell (vga to hdmi adapter), but I am not 100% sure.

Well, the exact naming of the adapter will depend on the vendor, but most vendors put the video source (computer) before the "to", and the video target (monitor) behind it. So "HDMI to VGA" would be an adapter for connecting an HDMI output to an VGA input, which is what you need. But the naming convention is not universal.

Note that HDMI-VGA adapters usually only work in one direction - so check the description for the adapter before buying, so you get the right adapter.

I have seen some people in online forums talking about active and passive connector. It is turning me crazy. I can't really grasp that. Can you tell me like a layman, what should I be using?

A "passive connector" is a connector that does not "do" anything - which means it does not have electronics inside that convert the signal. Instead it only electrically connects different plugs. That only works if the required signal itself is the same on both sides (or compatible). So passive connectors only work in certain situations. For example, you can go from DisplayPort to HDMI with a passive adapter (because DisplayPort was designed that way).

HDMI and VGA use completely different signals, so you need an "active connector" (or "active adapter"), which contains electronics that will convert the signal.

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Further reading: How to convert HDMI to VGA or VGA to HDMI . This article gives more explanation about the technology required.

Wikipedia also has a section on HDMI to VGA conversion: HDMI - Legacy compatibility

Comments

[Mathew Lionnet]

I would recommend to not bother with adapters and vga signals just get new monitor. If it’s a budget issue, get a used one, many offer hdmi+vga inputs (if you still have vga sources). However as a road warrior - presenting with various unknown projectors on events- it might be a good idea to have a hdmi-toßvga dongle in your pocket. (Btw some Dell laptops have Display Port not HDMI connectors, make sure to check.

[Criggie]

@eckes agreed - commenting because its not an answer, but OP needs to price the active adapter, and compare that with the cost of another monitor. The adapter could easily be a hundred europounddollars. An ex-lease one can still be great - an LCD monitor that only has VGA is going to be pretty old, fuzzy, and higher power usage. And if its a CRT, then just don't even bother.

[qsaso]

Is it really not worth it to get hdmi-to-vga-adapter? @criggie. My purpose is mainly for reading pdfs.

[Andy Hames]

@Criggie Seriously, 'a hundred europounddollars'? Active HDMI to VGA adapters are listed on Amazon today for under £10 (US$13, €11). Even a HDMI to VGA+DVI+HDMI+Audio multi way adaptor is less than £20.

[Boann]

@Criggie They're on eBay for $2 shipped (if you're willing to wait weeks for it to arrive). I've used them before and they work perfectly.

[Gábor]

@qsaso That's not easy to answer because only you can decide whether you can and want to afford a new monitor instead. But if the monitor is a flat LCD (not some really old CRT), then using its VGA input involves an analog-to-digital conversion inside the monitor (because VGA is analog but the pixels you end up looking at are driven digitally). And you buying an adapater will do the opposite. So, just to use the old monitor, you'll do a roundtrip of digital-analog-digital that's utterly unnecessary, and will certainly degrade picture quality.

[Gábor]

The second leg inside the monitor might be marginally better but the odd Chinese adapter you will buy for a couple of bucks will certainly be just working, nothing more. Be aware that it might not even allow the resolution you normally use (or, will allow but with significantly lower picture quality). So, unless you opt for a more expensive adapter, you might just as well bite the bullet and move on from that old VGA-only monitor, anyway.

[Michael Hampton]

I'll second the advice to get a new(er) moinitor. I would save the antique monitor for my retrocomputing hobby...

[Chris H]

@Criggie when I bought some active HDMI-VGA adaptors for Raspberry Pis, they were cheaper than the dumb HDMI-DVI cables I'd have needed for use with a newer monitor - and the old VGA monitors serve another few years on data-collection rigs.

[Eric Towers]

"DVI-D and DVI-A use physically compatible connectors"... Sometimes. DVI-D female connectors are not required to have the four sockets to match the four DVI-A pins that carry the analog signals. More than one user has bent those pins irreparably by forcing. A DVI-A female connector is not required to have all 18 (single link) or 24 (dual link) sockets to accommodate the digital pins on a male DVI-D connector. More ruined cables. At least female DVI-I connectors will accept either kind of male connector.

[gronostaj]

You're missing one crucial detail. These adapters are directional. Your "VGA to HDMI" adapter won't work here because it expects input on the VGA side and produces output on the HDMI side. OP's laptop produces HDMI and they need to convert it to VGA, so a HDMI→VGA adapter is needed.

[Gábor]

No, sorry, completely wrong. Those needs don't depend on what cables you already have, they depend solely on what you want to convert to what. As the OP has a device that produces HDMI signal and a monitor that consumes VGA signal, there are no three choices. There's only a single one: converting HDMI to VGA. And there's no cable that does that, only an adapter because a complete circuitry is required to make that conversion. So, the other answers are about the correct solution. Yours isn't correct in any way, unfortunately.

[gronostaj]

Active adapters are directional. Exactly one end accepts input and exactly one produces output. They don't work in reverse. The picture you've posted is coincidentally the right one, but the other one (male VGA-female HDMI) wouldn't work.

[gronostaj]

@Eric Ah, the DVI virus!

[Boann]

You're not going to end up with the wrong one, because it's such a common use case.

[gronostaj]

Quote from OP: "Do I need a HDMI-to-VGA adapter or VGA-to-HDMI adapter? My common sense would tell a VGA-to-HDMI adapter [...]". They would've bought the wrong one.