Power Distribution Board
1. Introduction
I have found that having 19VDC available on the workbench is very handy for powering the various devices such as lights, audio amplifier, RPis, low-voltage power supplies and other various bits of test equipment.
An old laptop power supply provides 19V at 4A and this PCB provides two fused groups of three outlets each, each group with a ‘power-available’ LED indicator. I figure a big fuse for higher powered devices and a smaller fuse for lesser devices.
3. PCB
4. Etching
The Toner Transfer Method works okay on boards with big, chunky traces like this one. Knowing how much heat to apply with the iron is a bit of a hit-and-miss affair. I touch up the traces with a 1mm ‘paint pen’ prior to etching.
The yellow paper has a waxy coating on one side. Too much heat and the wax adheres paper fibres to the board and much scraping is required to remove it. Glossy magazine paper might be better but I haven’t tried that yet.
The board was then etched in approximately equal volumes of 32% HCL from the swimming pool shop and 3% H202 from the supermarket. Etching took maybe 10 or 15 minutes to get started but then proceeded quite quickly, taking prehaps another 5 minutes.
5. Construction
While I was at it I decided to make two boards as another is sure to come in handy sometime. They came out okay.
The toner transfer works well as a pseudo silkscreen layer on the boards’ front. Without the copper to absorb the heat, very little ironing is required.
- The fuse holders are for the smaller 5×20mm fuses, with 22mm pitch.
- The green connectors are common but are hard to find because they don’t seem to have a common name. In Kicad, I have them named as 5EHDR-3-P5.00mm and 5EHDR-2-P5.00mm. I believe that the original manufacture is a company called Dinkle. Tayda Electronics have them listed along the lines of 3 Pin Male Pluggable Screw Terminal Block 5.08mm Butting Style and specify: Manufacturer: ULO, Series: TB30-3P, 20A 300V
The old laptop PSU providing 19V DC for the workbench:
And the distribution panel, both mounted tucked up under the shelf:
All in all it was a very useful little project, and well within my home-made PCB manufacturing skills.
