Category Archives: Learning

Learning the Art of Electronics: 1S Supplementary Notes: Investigating Thevenin equivalent of voltage divider | In The Lab

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This post is part of my video blog and you can find more information about this video.

Silly Job Title: Luminary Luminar. I am the Luminary Luminar!

In this video we continue to work our way through Learning the Art of Electronics. In this video we finish 1S Supplementary Notes: Resistors, Voltage, Current and do Exercise 1.10 from The Art of Electronics which has us investigating a voltage divider.

In this video I recommend to you the book Schaum’s Outline of Basic Circuit Analysis, 2nd Edition and Gary Tuttle’s website gtuttle.net where you can find Thevenin & Norton practice problems.

We use the METCAL PS-900 Soldering Station for soldering.

We use the AiXun H314 Hot Air Gun for heat shrinking.

We use the Pro’sKit SS-331H Desoldering Pump to fix up some of our mistakes.

We use the Tenma 72-10505 Bench Power Supply to provide 15 and 30 V DC to our circuits.

We use the EEVblog BM2257 Digital Multimeter to measure voltage.

We use the Fluke 17B+ Digital Multimeter to measure current.

We use eight of the cheapo Yum Cha DT830B Digital Multimeters as ammeters and voltmeters.

We use the Brother P-Touch D210 Label Maker to label our circuit.

We use the Sharp EL-546L Scientific Calculator to do some basic calculations.

We use the Bysameyee Head-Mounted Magnifier to light up our life.

We use the nmsafety Nitrile Gloves to protect our fingers.

We use the ElectroCookie PCB Prototype Solderable Breadboard to make our circuit on.

We use the WilliamKlein Music Stand to hold our tome.

We use the Scotch Titanium Scissors to snip, snip, snip.

We use the Hakko CHP 3C-SA Precision Tweezers for tweezering.

We use the Plato Model 170 Wire Cutter to cut, cut, cut.

We use the Kaisi S-160 45x30cm Repair Mat as our workspace.

Thanks very much for watching! And please remember to hit like and subscribe! :)

p.s. today I added Luminar, Pro’sKit, Desoldering, Tenma, Yum Cha, Multimeters, Bysameyee, nmsafety, ElectroCookie, Solderable, WilliamKlein, and Hakko to my spell check.

Following is a product I use picked at random from my collection which may appear in my videos. Clicking through on this to find and click on the green affiliate links before purchasing from eBay or AliExpress is a great way to support the channel at no cost to you. Thanks!

Yum Cha 10pcs Glue Removal Razor BladesThis is an image of the product.

Let’s go shopping!

The Bang Preventer – aka DIY Current Limiter with isolation transformer

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I asked Tony359 about his current limiter and he referred me to the video below in which he explains his home made contraption. Very cool. I think I should make one of these.

Update: I also found a video covering a similar topic:

The voltmeter used in the second design is this one: Digital AC Voltmeter.

Oh, and here’s another one!

Electronic components to avoid in a product

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In this latest video from John Teel, electronic components to avoid in a real product:

  1. USB Micro-B Connections → use USB-C instead
  2. Through-Hole Components → use SMD instead
  3. Barrel Jack Power Connections → use USB-C instead
    • Note: 5.5 × 2.1 mm (5.5×2.1mm) is the common DC barrel jack size, 5.5 × 2.5 mm (5.5×2.5mm) is less common
  4. Unshielded DC-DC Converter Inductors → use shielded inductors instead
  5. Cheap No-Name Electrolytic Capacitors → buy from reputable brand instead, or, better, switch to ceramic or polymer aluminium capacitors
    • If you want no surprises, stick to: Nichicon, Rubycon, Panasonic, Nippon Chemi-Con (aka United Chemi-Con), Elna
    • For professional/industrial designs, also consider: KEMET, Vishay, TDK
  6. Bare Pin Headers as Production Connectors → use connectors rated for your application instead
  7. Mechanical Relays → use solid state instead, for DC consider MOSFET
  8. Single-Source or End-of-Life Components → use widely available components instead
  9. Counterfeit of Clone ICs → buy from authorized distributors instead:
  10. Hobby-Grade Sensors → look for higher grade instead with I2C or SPI digital interfaces

Git Commands to Run Before Reading Any Code

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Via Hacker News today was The Git Commands I Run Before Reading Any Code. I made a git-rep.sh script based on these:

#!/bin/bash

# 2026-04-09 jj5 - SEE: https://piechowski.io/post/git-commands-before-reading-code/

main() {

  set -euo pipefail;

  report 'What Changes the Most';
  git log --format=format: --name-only --since="1 year ago" | sort | uniq -c | sort -nr | head -20;

  report 'Who Built This';
  git shortlog -sn --no-merges;

  report 'Where Do Bugs Cluster';
  git log -i -E --grep="fix|bug|broken" --name-only --format='' | sort | uniq -c | sort -nr | head -20;

  report 'Is This Project Accelerating or Dying';
  git log --format='%ad' --date=format:'%Y-%m' | sort | uniq -c;

  report 'How Often Is the Team Firefighting';
  git log --oneline --since="1 year ago" | grep -iE 'revert|hotfix|emergency|rollback';

}

report() {

  echo;
  echo "$1":
  echo;

}

main "$@";