-2

lets say I loose the acdc adapter of a device, like a laptop or a wireless router, how do you know that another adapter will work with my device? my assumption is that I have to match the same voltage and the amperes have to be equal or higher than the missing adapter. But I heard of people that just used an adapter that fit in the device and even with very different voltage specification the device worked, were they lying?.

And another thing: does some adapters just rectify the input making not suitable for other devices that require constant current?

I hope I am asking this in the right page, if not I'm sorry.

user1006274
  • 103
  • 1
  • read through this thread: [Choosing power supply, how to get the voltage and current ratings?](http://electronics.stackexchange.com/questions/34745/choosing-power-supply-how-to-get-the-voltage-and-current-ratings) – Nick Alexeev Aug 11 '13 at 01:29
  • "But I heard of people that just used an adapter that fit in the device and even with very different voltage specification the device worked, were they lying?" No, some devices have a regulator inside that accepts a wider ranger of voltages. But a laptop is probably not one of them. A router, it can, but unless you open it up to check, it's a gamble. – Passerby Aug 11 '13 at 03:39

2 Answers2

1

But I heard of people that just used an adapter that fit in the device and even with very different voltage specification the device worked, were they lying?.

No, but the components in the device might wear out faster. There is a certain amount of give in the requirements, but it is generally best to stick with what the manufacturer recommends.

And another thing: does some adapters just rectify the input making not suitable for other devices that require constant current?

Absolutely correct. Some devices can deal with large amounts of ripple (usually because they have some filtering on the power input), whereas others will fail, often in spectacular ways. Very few wall warts have any actual regulation though.

Ignacio Vazquez-Abrams
  • 48,282
  • 4
  • 73
  • 102
  • I disagree with the last sentence that very few wall warts have actual [closed loop] regulation. Most contemporary wall warts have flyback topology with a closed loop controller and feedback loop through opto-coupler or through sense winding on the flyback inductor-transformer. – Nick Alexeev Aug 11 '13 at 03:45
0

Your assumptions are ok but with the understanding, that not all designs are so tolerant, but good ones are.

Constant current sources are normally used in such devices as LED strings that do not have current limiiting resistors.