Fuse Position?

Hello,

I stumbled across this site whilst trying to build a PSU for a guitar effects pedal.
The circuit diagram is great, but the fuse seems to be in the wrong place? Shouldn't it be on the HV side of the transformer?

Posted by Richard Senior (mec@richardsenior.freeserve.co.uk) on 04/03/2004, at 00:54 GMT

OOPS!

Sorry, on the schematic for the PSU here :
http://www.eleinmec.com/article.asp?16

The fuse specified is a 240v fuse according to the maplins code?

Posted by Richard Senior (mec@richardsenior.freeserve.co.uk) on 04/03/2004, at 00:59 GMT

Fuse both sides

Well, there should be fuses on *both* sides of the transformer. The 1A fuse is there to protect the secondary winding if there is a fault in the PSU or the circuit it is powering.

You would also have a normal mains fuse on the primary winding side of the transformer, as you would with anything mains powered. It is not shown in the article because the transformer is not shown!

I am trying to discourage people from dabbling with the mains side of things, as it is preferable and safer to use a ready-made mains transformer, such as the 12V ones used in model railways, or the 'brick' type power adaptors which you can get in non-smoothed or regulated versions.

Posted by Tim Surtell on 05/03/2004, at 16:13 GMT