DC adapter question..

Posted by: JaBZ

DC adapter question.. - 24/06/2006 07:35

Thought I'd pose this question for you electronics guru's
I have a Lacrosse projection clock imported from US, which came with a (110v) DC adapter that outputs 3.4v 100mA. I am finding it difficult to source a (240v) DC adapter that outputs the same voltage, this is compunded by the fact that the plug is angled and small (fits into bottom of clock)..

I can find lots of variable voltage DC adapters both regulated and unregulated that output 3, 4.5, 6, 9, 12 volts.
Would powering this clock with one of these unregulated adapters set at 3volts do any damage? Is it correct that using an unregulated adapter with more than the required amperage mean the adapter will supply slightly more voltage?
Posted by: Shonky

Re: DC adapter question.. - 24/06/2006 08:27

Quote:
Is it correct that using an unregulated adapter with more than the required amperage mean the adapter will supply slightly more voltage?

Yes. But how much depends on what current rating the transformer has.

Personally, I'd probably try a 3V regulated supply and see if it works and go from there
Posted by: mlord

Re: DC adapter question.. - 24/06/2006 11:30

Quote:
Quote:
Is it correct that using an unregulated adapter with more than the required amperage mean the adapter will supply slightly more voltage?

Yes. But how much depends on what current rating the transformer has.

Personally, I'd probably try a 3V regulated supply and see if it works and go from there


Yeah. The product page even says it's made to run on 3VDC, so that should work.

-ml
Posted by: Shonky

Re: DC adapter question.. - 24/06/2006 11:35

I hadn't looked at the product page until now. It says it runs off 2 x AA (i.e. 3V). The manual actually says the adapter is 6V/100mA
Posted by: JaBZ

Re: DC adapter question.. - 25/06/2006 22:56

Yea I think the manual is wrong, I've got the adapter in my hands and it says the output is 3.4v unless the clock can handle upto 6v but I'm not willing to find out.
I may just end up buying this and plugging the adapter into it.
Posted by: mlord

Re: DC adapter question.. - 26/06/2006 01:34

Quote:
Yea I think the manual is wrong, I've got the adapter in my hands and it says the output is 3.4v unless the clock can handle upto 6v but I'm not willing to find out.


MMmm.. perhaps it has internal voltage regulation -- risky to experiment and find out (or not!) though.

The Alcatel Speed Touch xDSL modems are like that here. Various models from various ISPs are provided with AC adapters whose outputs range from +9VDC to +18VDC, and they're all interchangeable.
Quote:

I may just end up buying this and plugging the adapter into it.


Sensible, and reusable for other stuff in the future. I seem to recall Mach having a huge transformer in the flat in Paris, with lots of USA audio gear plugged into the output of it.

Cheers