The power supply project

Progress… it’s good

Okay! So I’ve finally got back into electronics (hence why I haven’t used this blog much, been in my basement lab, recently set up) and revitalized a few projects from 2009ish that I’ve been dying to build. Top of the list is a bench power supply. Back then, I hacked an old computer PSU to make a quick, variable output power supply and it’s “ok”. Turns out “ok” just isn’t good enough.

To start with the thing is bloody noisy. It’s an old switchmode and my scope says it has a huge ripple of 50-80mV! That just … sucks if I’m trying to do anything serious and especially sucks if I am trying to do anything digital (though I’m still very much in analog mode at the moment). Sure I could have added a ton of filter caps on the output to reduce it, maybe a common-mode choke but really, who wants to do all that mess? A better design from the start will work better and the plus is I can say I built an accurate lab power supply.

So, I researched about a billion plans to come up with a workable, linear power supply design. The basic specifications are as follows:

  • Adjustable voltage output of 1.2-30Vdc
  • Adjustable current limiting of 1mA to 3A
  • Symmetrical +/- and tracking
  • Fine, linear control of the voltage and current
  • Adequate circuit and mains protection
  • Long life and easy repairability

Not insurmountable. In fact, done many times before by practically every electronics hobbyist. Sort of like a carpenter building his own workbench, the electronics hobbyist builds his (or her) own test equipment. Sure, I could buy a commercial one that fits these criteria (or most of them) for around $200 (and I’ve already spent more than that) but I want it to be mine. My design, fitted to my needs.

I’ve started writing actually late into the design of it, and have actually started building modules of it I was sure about. I’ve created this category to track this, and my other electronics build projects.

Though I realize very few people will read this blog, I hope the few that do can chime in with suggestions, I am still very much a novice and if you see anything glaring or have something helpful to share with me, that would be most welcome.

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