Homebrew Power Supply

I'm in the midst of designing / building a homebrew 220VAC to +12VDC / +5VDC power supply for the Remote Controlled AC Outlet projects. Not much else to say, just throwing up some pictures for now.

Oh, I will say this - if you are working with the mains voltage, BE CAREFUL. Sparks, smoke and flames are the least of your worries - electrocution and DEATH is what you should really worry about.

Here's an application note from MicroChip about transformerless power supplies: AN954

1st gen power supply design (right), connected to a PIC board (left)
It worked, but it shocked the heck out of me

when I touched the PIC board. And in the process,
it took out one of the LEDs.

2nd gen power supply design (+5VDC only):
Adding the choke and large cap to the output

eliminated 'shocking'.

2nd gen power supply design (+5VDC only):
Side view

2nd gen power supply design (+5VDC only):
Bottom view, showing the bridge rectifier

3rd gen power supply design - Safety components added:
3A fuse and a MOV added to input side of circuit
(side view)

3rd gen power supply design - Safety components added:
3A fuse and a MOV added to input side of circuit
(top view)

 

3rd gen power supply design - Potting the heck
out of the back side (using hot glue)
to help prevent a shock hazard

3rd gen power supply design - Testing with a PIC/LED
board to ensure that the PIC load can be handled.

3rd gen power supply design - Installed inside the
Remote Controlled AC Outlet project. Fits nicely to
the side with no problems.

 3rd gen power supply design - The Remote Controlled
AC Outlet project buttoned up with the new
power supply inside. Much cleaner project now.

3rd gen power supply design - The external ugly
black lump of a power supply that was slung external
to the Remote Controlled AC Outlet project. This
was replaced with the 3rd gen power supply.



3RD GENERATION POWER SUPPLY SCHEMATIC

Update 12.1105:
I've complete a second power supply. More compact and I change the 470 ohm resister on the front end to a 22 ohm. It doesn't get as warm now and it still provides (basically) the same current:

Neater. Cooler (temp-wise). More compact.

 Solder side. No crossed traces. Nice!

 Front end components, all jammed together.
The bridge rectifier is under the large red capacitor
and the back end choke.

Back end components. There are zeners and resistors

hidden behind the caps.