Can I use this old Transformer for wall socket for Arduino UNO

I found a transformer cable that reads 5V—1A. Id love to be able to salvage it and use it for my arduino projects.

Would it work for plugging into the UNO’s barrel jack?

Only if it fits.

C'mon - unless you provide a perfectly focussed and detailed photograph of it in good light (daylight), we aren't interested.

Why would the way it looks affect anything if I posted the V and A? I'm not being a smart as, I really want to know

5V AC, or 5V DC?

If it's 5V, it's not suitable for plugging into the Arduino's barrel jack. After the regulator, it will only be about 4V.
And you haven't mentioned if it's regulated, or for that matter, if it's DC or AC. (As CrossRoads also just pointed out, I see.)
You mention a transformer (cable?). The output from a transformer is AC.

A photo would help.

It's a 120-240v to 5vdc---1A.

Marciokoko:
It’s a 120-240v to 5vdc—1A.

Regulated? (I did ask.)

Still no photo, too. Why do you insist on making it so hard for people to help you?

I always salvage old wall transformers. If they say 5 v. dc, 1 amp., they will probably deliver that. Get a voltmeter, and check to make sure it's as labeled. And be careful about the polarity of the plug. Most of them are center connector positive.

If you in fact put it into use, and the voltage reads low, you aren't likely to have hurt anything.

jrdoner:
I always salvage old wall transformers. If they say 5 v. dc, 1 amp., they will probably deliver that. Get a voltmeter, and check to make sure it's as labeled. And be careful about the polarity of the plug. Most of them are center connector positive.

If you in fact put it into use, and the voltage reads low, you aren't likely to have hurt anything.

Many aren't regulated, and can be over 5V under low load conditions. And a regulated 5V still isn't suitable for the DC input plug on an Arduino. The regulator will drop out.

If it is regulated, it could be connected to the 5V rail.

I'm not at home but when I get there I'll take the pic. How do I know if it's regulated?

Marciokoko:
I'm not at home but when I get there I'll take the pic. How do I know if it's regulated?

Got a multimeter? Measure it under no load, then with a load. The voltage should stay at 5V.

But a 5v DC wall wart supply plugged into the UNO DC barrel jack is still mostly useless, whether it fits or not.

Yes, if it is regulated, then connecting to 5V/Gnd on the Power header would be better. Be sure not to get them connected backwards!
Or connect via the USB connector, hack up a USB cable.

Here it is:

walladapter.png

Still... not enough volts...

As mentioned, the jack on the UNO needs 7+ volts.
What you have is a switcher regulated power supply, in a black
plastic wall wart.
One can tell this because of the wide range of input voltages.
It is still possible to use the socket with a jumper wire soldered
from it to the 5V rail or connect it through the header pins.
As was mentioned, you could modify a USB charger
cable to plug into the USB port.
That is safer than the jumper, should you forget the jumper and
plug in a 12V power supply.
Dwight

dwightthinker:
One can tell this because of the wide range of input voltages.

No, one can not. That is often provided by means of selectable series diodes, fed from a mains frequency transformer and rectifier circuit.

aarg:
No, one can not. That is often provided by means of selectable series diodes, fed from a mains frequency transformer and rectifier circuit.

Oh come on! That is ridiculous. Show us a reference!

The actual concern is that some of these power supplies have primary-side regulation only, which is poor.

Paul__B:
Oh come on! That is ridiculous. Show us a reference!

The actual concern is that some of these power supplies have primary-side regulation only, which is poor.

Okay. You don't believe me. I also couldn't believe that such a dumb system would be used. But I disassembled one once, and what I found was a diode chain. Here is an example device:

I can't swear that this example has it, but I'm pretty sure it's the same deal. Look at the sliding switch. It has a wiper that selects the number of diodes.

Okay, I see my mistake. We were talking about input voltage range on the line side. Not the output voltage. If it can accept a range without a switch, then yes, it's obviously a switcher.

OK so I just toss it?

I understand the USB cable transformation. What you're suggesting is I cut the transformer cable and a USB cable and patch the transformer to feed power via the USB terminal instead. But I'm not sure I...oh well, actually it might be a nice setup...I'll try it