Step Down Transformer 220V to 120V

Thread Starter


Joined Dec 28, 2015
Hi Guys

Found loads of step down transformers on the net but looking for a little bit of advice.
As always, when buying parts like this I would like it to be reliable, but more so safe....I've seen hundreds of phone PSU's etc etc from eBay that are so unsafe and don't want to end up with a cheap Chinese knock off copy.

Essentially I am looking to step down 240V to 120V, needs to be able to provide about 37W of continuous power, although higher would be better I guess so it's not working at max load.

Ideally would fit a UK plug socket, and give the ability to plug in a 2 pin euro style plug but if need be I can use an adaptor.
It'll be running a silent fan heater (to dry Motorcycle gear) more of a dehumidifier than a dryer and would be left unattended for 8hours plus



Joined Jun 2, 2008
A power tool isolation transformer would be supply more than enough but they are a little costly and you'd have to buy a plug. Something like this.


Joined Jul 18, 2013
If you only need AC then any small ~50va 240/120v transformer should work.
phone PSU etc are usually SMPS DC supplies, which you don't really need for a fan heater.


Joined Nov 4, 2013
If you want to go DIY a multivolt input lighting ballast for HID type lights makes for a pretty good step up/down auto transformer plus they can usually be found dirt cheap as well. ;)

Thread Starter


Joined Dec 28, 2015
Are you sure it only takes 37W.
It would seem that a fan heater would take more power then that.
Yeah, just checked it. 37W. Remember, it's not a fan heater, it's more of a dehumidifier so very low power consumption.

the yellow converter posted above is a little, err powerful at 750w and a little bit bulky and expensive consideri Ng I don't me ed


Joined Feb 5, 2010
Transformers work most efficiently when fully loaded.
It seems backwards, but the magnetic Flux density in the transformer steel is highest when the secondary is open. It is lowest when fully loaded.