Question about order of PSU, switch
MakerNewbie wrote 07/17/2016 at 16:31 • 0 pointsI'm retrofitting an old clamp-on desk lamp with LEDs. The original button switch (which I'd like to keep) is in the swivel head on the lamp. I plan to put the wall wart inside the lamp's metal base where the old ballast and transformers were located.
My options are:
1) Keep the wall wart on permanently energized with no load, and run the 12v output through the switch (this is the easiest option).
2) Run the mains to the switch and back down to the PSU so it is only on when the lamp is in use
Are there any good reasons to do #2, or can I just go with option #1? The only concern I have is maybe whether the PSU will put off heat even without load, and how that might compare to the heat of the original parts, or whether the heat would eventually do in the PSU.
Also, my 12v 1Amp wall wart is sizeable, so I may have to remove it from the plastic casing before inserting it in the base cavity of the lamp (of course I'd make sure nothing could contact the metal enclosure. Not sure if the idea of taking the PSU apart will affect anyone's input.
Thanks!!
Discussions
Become a Hackaday.io Member
Create an account to leave a comment. Already have an account? Log In.
I did something similar, but the lamp came with a inline switch on the mains, which I've spliced into the mains for the PSU...
I had the same thoughts, and decided that, minimal as it would be, I'd prefer it not be drawing current when off...
Are you sure? yes | no
The main reason for number 2 is that with number 1 the PSU will use power all the time. Not necessarily a lot, but that depends on the PSU. Of course, that would also create heat, and also reduce the lifespan of the PSU. So if possible, go for number 2.
If anything, removing the plastic casing is all the more reason for doing it that way. But if you do remove the plastic, make sure the lamp base is grounded seeing it is metal, or at least add a layer of suitable insulation completely surrounding the PSU – this is rather important for safety, and in fact is probably legally required (although I cannot say that it is adequate in that regard!).
Are you sure? yes | no