3VDC 2A power supply

[laudrup]

Hi,

I am trying to buy an ac adapter to hook up a Rosahl MDL-3 dehumidifier. The power supply requirements are listed here on page 2 for the device: http://www.rosahl.co.uk/wp-content/uploads/2013/02/RB-OP09001AMDL-instruction-manual.pdf

The problem I am having is that most of the ac adapters available at Jaycar or on the internet don't go into this level of detail on their specifications.

I came across the following 3V 2A ac adapter on eBay.

http://www.ebay.com.au/itm/BRAND-NEW-3V-2A-AC-DC-Power-ac-adapter-Power-supply-/290565341956?pt=AU_Electronics_Batteries_Chargers&hash=item43a70b4304&_uhb=1

Again the specs are not really specific, but based on people's knowledge of these kinds of devices do you think this is likely to meet the specifications for the dehumidifier?

(I am going to have the dehumidifier attached to a plug and play humidity controller that measures the humidity in a chamber and then switches the plugged in device on or off depending on this measurement)

Many thanks.

[Paul Rose]

The key requirement on the dehumidifier is the over current protection. 

The hint is that fold back style may not work.

This probably means that the element will "try" to draw more than 2 amps initially and draw less as it gets going.

Constant-current style limit supply will limit the current to 2A by lowering the voltage and increasing it as the current draw lessens. 

The foldback style may get stuck low after the initial overload, which is good protection for the pass transistor in the supply, but not useful for this particular application.

The e-bay listing only says that there is overload protection, so you can't tell.

A clue is that it supports 100-240v input, so it is very likely a switcher.   Maybe somebody will know what style of current limit typical wall-wart switcher uses.