Which voltage?

ednotdave

Please help!

I have an electronic decalcifier (descaler) unit that says:
Operating voltage: 6-15Vdc, Current consumption: < 130mA

I want to power this with a universal power supply that says:

Unregulated 3-12 V
Output: 3, 4.5, 6, 7.5, 9, 12v
300mA
3.6VA Max.

Which voltage setting should I use (and why)?

Thanks in advance, Ed.

T4i

Try 9v and if it doesnt work like it should try 12v. Both are within the operating tolerances.

ednotdave

With this item, it's impossible to tell if it's working properly!

Am I right in thinking that using a lower voltage would be safer (for the item being powered) than a higher one?

criminal_smile

Not going to make a difference. As T4i has said, all the voltages on your power supply fall within the safe operating range of your descaler. It needs at least 6V to work, but can operate with 15V as well. I'd go with T4i and run it at 12V, should be fine there.

djohn2002uk

ednotdave wrote:

With this item, it's impossible to tell if it's working properly!

Am I right in thinking that using a lower voltage would be safer (for the item being powered) than a higher one?

I would go along with your assumption. Any appliance that is capable of running on 6v satisfactorily should be run at 6v. This is not to say that it wont run "ok" at 12v and the likelyhood is that the the power supply you are using is unregulated anyway, which means that the appliance will "pull the voltage down" to around 6 or 7v. But I just see no reason to select a higher voltage if, as in your case, it is totally unnecessary.

ednotdave

djohn2002uk wrote:

I would go along with your assumption. Any appliance that is capable of running on 6v satisfactorily should be run at 6v. This is not to say that it wont run "ok" at 12v and the likelyhood is that the the power supply you are using is unregulated anyway, which means that the appliance will "pull the voltage down" to around 6 or 7v. But I just see no reason to select a higher voltage if, as in your case, it is totally unnecessary.

Yes, it is unregulated - and someone has just told me that if I use, say, 12v and the unit draws little current, then the actual voltage could jump to around 18v, which could be high enough to cause damage!

So, I think I'll try 6v...

...Thanks to everyone for replying.

djohn2002uk

What "Someone told you" is absolutely right, that is partly why I said stick to 6v.