Thursday, 2 February 2012

Universal Laptop Power Supply Further Update

After using this for a while, I've made a few changes. The power LED was wired in place of the original on the unit and wasn't ideal. As there is a delay in starting, it doesn't light immediately, and if there isn't much load it doesn't go off immediately. The combined with a possibly dodgy mains switch led me to make a change. I also thought a couple of 4mm posts would actually be a good idea, to make the unit more general purpose, so time for a bit of rework.

I added the 4mm posts and a new 'output on' LED wired across those (well almost +V is taken from the input side of the ammeter so as not to show up on there. I also removed the original 10K divider resistor from the main PCB and replaced it with one directly on the output, to remove any voltage drop from the internal wiring and the ammeter.
I replaced the faulty mains switch with a chunkier one and added a mains LED. I replaced the mains socket on the PCB with a 0.156" header to tidy up the wiring.

And now here is the finished unit, next to my existing 5V / 12V bench supply.