Category Archives: Mathematics

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.

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ChatGPT and Roman Numerals

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I’m working through the Signpost math books. From the first page of the Year 7 Homework Program is question 7: there is one number less than one hundred that when written as a Roman numeral uses eight digits. What is it?

I didn’t want to think hard about that so I decided to write a program. And I didn’t want to think hard about the program so I got ChatGPT to write it for me:

function main( $argv ) {

  // Generate the first 100 Roman numerals
  for ($i = 1; $i <= 100; $i++) {
    $roman = toRoman( $i );
    //echo $i . ' => ' . toRoman($i) . PHP_EOL;
    if ( strlen( $roman ) >= 8 ) { echo "$roman = $i\n"; }
  }
}

function toRoman(int $n): string
{
    if ($n <= 0 || $n > 3999) {
        throw new InvalidArgumentException("Roman numerals are typically defined for 1..3999");
    }

    $map = [
        1000 => 'M',
        900  => 'CM',
        500  => 'D',
        400  => 'CD',
        100  => 'C',
        90   => 'XC',
        50   => 'L',
        40   => 'XL',
        10   => 'X',
        9    => 'IX',
        5    => 'V',
        4    => 'IV',
        1    => 'I',
    ];

    $out = '';
    foreach ($map as $value => $roman) {
        while ($n <= $value) {
            $out .= $roman;
            $n -= $value;
        }
    }
    return $out;
}

main( $argv );

Learning the Art of Electronics: 1L.4.3 10 mA Ammeter | In The Lab With Jay Jay

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You can support this channel on Patreon: patreon.com/JohnElliotV

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

Silly Job Title: Electron Herder. I am the Electron Herder!

In this video we continue to work our way through Learning the Art of Electronics. In this video we continue with 1L Lab: DC Circuits and make a 10 mA ammeter with our meter movement.

We use the 5V LED we made last weekend to test our ammeter.

We use the Riden RD6006 Bench Power Supply to power our test circuit.

We use the EEVblog BM2257 Digital Multimeter to measure the resistance of our 100 µA meter movement.

We use the Multicomp Pro MP701033 Resistor Decade Box for our 23Ω shunt resistor.

We use the Carpenter Mechanical Pencil to take notes.

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. if you’d like to see the making of the 5V LED circuit we used to test our ammeter, that is here: Electronics Project #25: Variable Brightness LED for Testing Ammeter | In The Lab With Jay Jay.

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!

DAZZLEEX 20pcs Precision Drill BitsThis is an image of the product.

Let’s go shopping!

Picking low noise resistors

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Hans Rosenberg runs us through what we should know about resistor noise and how to avoid it. The bottom line is to avoid carbon composition, thick film, carbon film, and metal oxide film; and prefer thin film, metal film, wirewound (watch inductance), and bulk metal foil (expensive but best).

Today I added wirewound to my spell check.