AC/DC converter for LED lamp

[Cudzoziemiec]

It's for a bedside lamp type thing, the lamp itself still works but the converter brick wotchamacallit is broken - I know it's this cos at one point we had two lamps and two power wotsits, one working and one broken. The power supply is marked 12V DC 150mA. I've found another one, from a battery charger, which 12V 1.2A. Same connectors. So the question is simple - will the difference in amperage matter? The one from the lamp is marked "power supply" and the battery charger "AC/DC switching adapter" if it makes any difference, and both have the same " - . + " symbols.

TIA

[Ham]

Nope, will be fine

[clarion]

Are You Ready?
Flick of the Switch
Danger
High Voltage

[Biggsy]

The current (Amps) rating of an adapter is the maximum safe amount to draw, so it can be higher than the appliance needs, but it should not be lower.

"Switching" means the adapter adapts the voltage by rapidly switching on and off.  These are more efficient than old-style transformers that just use big coils.  You can tell by the temperature.  The cooler it runs, the less power is being wasted as heat.  They tend to be lighter as well - a way of quickly guessing what type an adapter is if it's not explained on the label.  "Efficiency level V" is currently the best, by the way.

[Biggsy]

Warning!  Dangerous ear worm:

<a href="http://www.youtube.com/v/2a4gyJsY0mc&rel=1" target="_blank">http://www.youtube.com/v/2a4gyJsY0mc&rel=1</a>

[Cudzoziemiec]

But that's nothing like AC/DC!

Thanks for the answers.

[clarion]

But that's nothing like AC/DC!

See Reply #2

[aidan.f]

It may  be  operating in constant current, not  constant voltage mode when used for an LED lamp. In which case  bigger is  most certainly not  better.

[Cudzoziemiec]

The current (Amps) rating of an adapter is the maximum safe amount to draw, so it can be higher than the appliance needs, but it should not be lower.

So the amount actually drawn is determined by the appliance but should not be higher than the rating of the adaptor - for example, a 3A adaptor supplying a 1A appliance will actually draw 1A?

[Kim]

Exactly.

[Cudzoziemiec]

Cheers.