A friend gave me his monitor but forgot the power cable.
I want to buy the power wire but I don't know which one is the right adaptor and plug.
Lifehacks Stack Exchange is a question and answer site for people looking to bypass life's everyday problems with simple tricks. It only takes a minute to sign up.Sign up to join this community
The display unfortunately doesn't give you all the information you need.
It does tell you the power requirement…
19V DC at 1.58A
You can use a power supply with a higher Amperage capability, but not lower.
The voltage must match exactly.
The input voltage will be, of course, your national mains voltage.
The issue comes in the plug…
Barrel jacks come in many sizes, some of them almost impossible to tell apart by eye. This is where any system with interchangeable multi-plugs comes in. Some of them have reversible polarity too - which is going to come in handy.
The second problem is that there is no indication of polarity.
The socket on the display really should have a polarity marker as well as the DC marker. This says "DC", though they'd already told you that in the info panel, in text & also using the same symbol
This is missing [source Wikipedia]
to indicate whether centre is positive or negative. So you're going to have to guess. One way will work, the other won't. The socket should have diode protection for if it's connected the wrong way.
So, figure out which plug will fit best first before adding any power [note barrel jacks rarely fit very snugly, so choose the first one in ascending size order that will fit over the centre pin without forcing], then quickly test the polarity both ways to see which works.
Pumping HP into HP display Lifehacks
The label you show has, "For applicable power supplies see user manual."
The (HP 24f Display User Documents) are rather opaque about part numbers but shows the following diagram for the power supply 'wire':
It is not a simple wire but an assembly that includes an AC to DC transformer.
You will probably have to contact HP support in your locale with the display model and serial number to get the proper part numbers from their parts list or you may locate what you need with a Web search.