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Footprint Update

A project log for Bench Power Supply

Designing an open source, modular bench power supply to rule them all.

the-big-oneThe Big One 05/21/2015 at 16:280 Comments

I decided to change the footprint from 3/4" particle board to 1/4" hardboard. The reason for this switch is mostly convenience: I have 3/4" #4 screws, but I don't have 1 1/2" #4 screws.

I have now also drilled the holes for all four channels' PCBs, mounted one channel, re-mounted the SMPSUs, and mounted the power rails. I had originally planned for the power rails to use screw terminals, but I think that directly soldering will give more resilience over time as well as make for a better electrical connection, at the expense of losing some flexibility.

Updated pictures are below.

Top view with approximate locations
Closeup of power rails. Two parallel wires connect to each connection in the SMPSU; one set of wires connects to each channel.

More wires

Bottom of the footprint. #4 screws are used to mount all the hardware; rubber feet will keep the screws off the table.

Closeup of a single channel mounted to the board. I still need to get some nylon nuts for the mounting holes right next to the heat sinks (I tried with metal nuts at first, and while it looks like they are not quite touching the heat sinks, and I have tested for continuity between the mounting holes and the heat sinks (there is no connection), I want to be sure that it does not short out later on. (The heat sinks are connected to live voltage: the transistor collector and the regulator VIN respectively, while the mounting holes are connected to ground).


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