Help with Power Adaptor

[Charlie]

Hi all,

I have a device that needs 5v DC - the supplied adaptor is broken (tested with a meter to confirm) The info. on that one was this:-

Output: 5V, 2000mA

I have another adaptor that has this info.

Output: 3V 80mA

The 3V adaptor outputs a reading of 4.5v on a meter

So do you think this one will do the job? Its not over powering, just under - I am more concerned with the much lower 80mA - Will this be an issue? It's not used to recharge a device but to just power it.

TIA

P.S - I don't know how much mA the device requires/draws - There is nothing in the manual or on the device

[gazzy21uk]

Hi charlie
I'm no electronics expert but that adapter would be a bit underpowered probably get to hot and die fast (drawing to much)also very important you need also to check the polarity of the adapter socket if + and - is the same you need something slightly above 200ma though don't quote me on this LOL .
Polarity is also next to where it tells you the voltage and current draw ma it's a round symbol (O sort of thing

you might be able to wire it to your a usb cable but google it first lol

[Charlie]

Thanks, just tried it anyway and it does not work - the lights are on but no one home. There just is not enough juice, I guess I was pushing it with 80mA - that is must be too low. - All ok on the polarity of the plug, I checked 1st that it matched the required (center + / outer - )

Going to hunt around in the garage for another adaptor.

[Mitre]

Have you not got an old usb style adaptor you can just cut the end off .all are 5v just make shure polarity is ok
Sent from my GT-I9100 using Tapatalk

[gazzy21uk]

yeah Mitre's right have done this on many things I think if I remember right usb is 5v up to 500ma
cut usb cable use red + and blacks N the other 2 wires you can cut off .

[Charlie]

Thanks guys, just found a 5v 2500mA adaptor in the garage, it works fine. Was going to do like you said, done it before but no need now. I do sometimes forget about the power draw and focus too much on the voltage - Doh

[Trashcooky]

Thanks guys, just found a 5v 2500mA adaptor in the garage, it works fine. Was going to do like you said, done it before but no need now. I do sometimes forget about the power draw and focus too much on the voltage - Doh

A bit late from me but just a thought Charlie, I have fried equipment using off-the-shelf generic power packs because of incompatibilities that aren't always immediately obvious.
Some equipment requires a regulated voltage input where a drift of more than say 5% may be critical to safe operation.
Also some power adaptors are full-wave rectification DC and other are only ½ wave rectification. Having only half-wave rectification can cause AC hum on any audio devices unless the output is heavily smoothed. You can usually tell if the original power pack was ½ wave by a dotted line ----- whereas a fullwave device shows a continuous line ____ and of course the voltage and current rating.

[Charlie]

Thanks @Trashcooky for the extra info, I did not know about the other info you posted, apart from using a regulated adaptor. Which I always use, unless the device that requires power has a certain range, ie 9v-12v.

Cheers

[gazzy21uk]

@Trashcooky nice info
I'm more of a plug and pray sort of guy

[Astro]

Hi @Trashcooky, you obviously know your stuff!

You can usually tell if the original power pack was ½ wave by a dotted line ----- whereas a fullwave device shows a continuous line ____ and of course the voltage and current rating.

Most of the power adaptors I've got show both a dotted and continuous line on the spec label... does that mean they are both full and half wave compatible?

Regards

Excel