I bought an electronic item in the US but I live in England. I bought the AC adapter for English version of the same piece of kit, which has exactly the same voltage and HZ specs. Yet it doesn't work. Is there a polarity issue I'm missing or something else. Or just a dodgy adapter?
Your adaptor, if designed to allow the kit to work on 220v 50 Hz., should just work out of the box. I'm not sure what you mean by "exactly the same voltage and HZ specs. " Your adaptor most likely is not going to change the 50 Hz. to 60 Hz. and there is no need to do so since the AC will most likely be converted to DC.
Thanks Tom. I mean that the adapter appears to output the same but the US mains input is obviously different from the UK mains input. I can see no reason why it wouldn't work if the output is the same and yet it doesn't. The only unknown is polarity.
There are cases where the frequency of the AC line will matter, but in those cases, the AC adapter will output AC. In some cases, that means only AC, and the rectification and filtering is inside the main unit. In other cases, it means an extra contact that supplies the required AC, so the AC can be used for some clocking purpose.
But then, in the former case, the adapter will be marked as outputting AC.
The example of the latter that comes immediately to mind is the AC adapter, which was more of a brick, for the Commodore 64. It supplied
9vac in addtion to +5 and +12v, since something in the computer needed
60Hz to keep track of time.
But even in that case, the wrong AC line frequency would not result in failure, just a slow clocking.
Well you have to measure the voltage at the connector and verify it is 5VDC preferably with a small load (less than 2.5 watts).
I guess that is difficult as you would not have asked the original question if your electrical knowledge was sufficient to do this. (No offence meant) Or get your local Computer tech to check it for you.
This would be an excellent time to invest in a cheapie digital multi-meter. You can probably find one for under US$10 (sometimes even $5 on sale). You don't need anything fancy for this.
I use my late father's philosophy that, where feasible, it is better to invest in tools (and learn to use them), than to pay someone else. That way after the job is done, you still have the tools and knowledge for next time. And often it is actually less expensive the first time, which is probably the case here unless your shop will test for free.
Bob Masta DAQARTA v4.51 Data AcQuisition And Real-Time Analysis
Scope, Spectrum, Spectrogram, Sound Level Meter FREE Signal Generator Science with your sound card!