High Voltage Differential Probe Design and Build - Part 1

This project will be made of multiple parts. First, I'll explain the basics of designing a differential probe then the following posts will be about how to actually do the math and lay out the PCB for something like this. But first thing's first: "Excuse me, how much is this?" Have you ever  wondered why are differential oscilloscope probes so expensive? Well, I have, and the answer is....out there?! No, seriously, I would accept a price...

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How I make my PCBs: Toner transfer and PCB etching technique

      I know there's a ton of blogs and articles on the matter of DIY PCB making, and for every hundred articles, there's a hundred different ways to do it.  So here, I'll just present you the way I do my PCBs. It's pretty simple and cost effective, not to mention I get good results...most of the time. Things needed: A4 Laminator (I use a Peach PL718) Glossy A4 paper (150 gramms) Ferric chloride A large glass bowl  An...

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Updates and Things to come

Just thought I should give some updates on my current projects that I' working on right now.      Currently I've bought an Arduino Mega for my Voltcraft DPS 4005 PSU repair and managed to wire everything up. I can now control the LCD as I wish, but currently struggling with getting the DAC to work. No matter how I drive the pins of the AD7541, I always get  8.9 Volts on  the output of the PSU. I thing there's something wrong with the pull-up resistors on  the DAC pins. So next step is to remove those and...

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Accu-check Blood Sugar Meter Teardown

Today, on the chopping block  we have an everyday (for some) medical equipment.   It's the Accu-Check Compact blood sugar meter. I got this, for about 6 Euros, because I was interested in what' inside one of these and how such a device actually measures blood sugar. Also I had a hunch that it may have some niece electronics inside which I could use in some other projects. Now, let's see what this baby looks like on the...

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What's this page about? Also first book recommendation

Maybe some of you are wondering what's this doing here? What's up with this? Well, in this section, I'll be posting  reference design books, service and user manuals for test gear that I own, schematics and so on, both to create a library of data for myself and also to maybe help others that are searching for ideas, manuals.... So, let me start this off with a recommendation for those that are just starting with electronics and also for those that have the experience but never managed to read this book: "The Art of Electronics" by Paul...

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HP 3478A Multimeter Power Button Fix

   In the post about the HP 3478A Multimeter Modification, I said at one point that even though there's that issue about the stuck power switch, it doesn't bother me that much. Well, it turns out that it did bother me. In fact it was down right annoying. Most likely because of my O.C.D. was acting up, knowing that there's something not quite right about the multimeter. So, rummaging through my collection of old miscellaneous "things"...

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HP 3478A Multimeter Modifications

    What kind of electronics engineer doesn't have a bench multimeter? Well, probably a lot, but since I didn't have any decent multimeter, aside from some very cheap UNI-T ones, I bought from eBay an old HP 3478A 5 1/2 digit multimeter. It'd old, I know, but it was "really cheap" (about 120 Euros) and only had some minor faults. I mean, what's a stuck Power button and a missing AMPs range fuse, right? So, anyhow, it arrived,...

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Teardown of an old russian C1-91 100 MHz, 2 Channel Oscilloscope

 I got this old relic for free from a very kind person, when I was still a student and working on my final year project. It's a great bit of kit, and, yes, it's a clone of the Tektronix modular scopes from the 80's, and yes, the labels are all in Russian, and yes, it takes 10 minutes for the CRT to actually show something....but hey, it did it's job.  But now, since I  got my new Rigol 1054Z and because the trigger on the old C1-91...

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Teardown of old NEC MultiSync MT Projector

        A few months ago I got my hands on an old NEC Projector from the local flea market for almost nothing (20 Euros or so). Of course, after carrying up the stairs to my apartment, which is no mean feat, because this thing weighs about 30 kilos, I followed the normal procedure for such a nice piece of old "vintage" electronic gear, which was to stand back and admire it. Ain't she a beaty?  After...

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Repair of Voltcraft DPS-4005PFC Power Supply - Part 1

            About a year ago I bought and old Voltcraft DPS-4005PFC  adjustable switchmode power supply, advertised as not working. It was missing the main controllers and also the two main switching transistors, but I thought I would give it a shot. I mean, if all else failed, I could rip out the rest of the bits in it and spin my own PSU. I thought it was a nice bit of kit: 0-40 Volts and 0-5 Amps, PFC,...

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