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Ohm's Law calculator and more.

Pommie

Well-Known Member
Most Helpful Member
On another thread a member wanted a parallel resistor calculator so I knocked one up in html. I then thought to combine a few different calculators onto one page.
The result is attached. Had to rename it .txt so rename it to .html and all should work fine.
A problem with storing html pages on your hard-drive is that if the page tries to access ANY file on your machine it's seem as a security risk and not allowed. There are ways around it (using location.origin) but it gets messy.
To overcome this I used inline SVG (Scalable Vector Graphics) to produce the two images on the Ohm's Law page.

Anyone that wan't to have a play with SVG can go to this page and copy and paste the following,
Code:
<!DOCTYPE html>
<html>
<body>
    <svg width="100%" viewBox="0 0 500 500">
        <polygon points="250,90 65,405 435,405" 
        style="fill:rgb(220,220,220);stroke:black;stroke-width:4;"/>
        <line x1="145" y1="270" x2="355" y2="270" style="stroke:black;stroke-width:4" />
        <line x1="250" y1="270" x2="250" y2="405" style="stroke:black;stroke-width:4" />
        <text x="225" y="195" style="fill:red;font-size:28px;">(V)</text>
        <text x="200" y="225" style="fill:red;font-size:28px;">Voltage</text>
        <text x="265" y="90" style="fill:red;font-size:28px;">V=IR</text>
        <text x="150" y="335" style="fill:blue;font-size:28px;">(I)</text>
        <text x="120" y="365" style="fill:blue;font-size:28px;">Current</text>
        <text x="20" y="295" style="fill:blue;font-size:28px;">I=</text>
        <text x="60" y="280" style="fill:blue;font-size:28px;">V</text>
        <text x="60" y="310" style="fill:blue;font-size:28px;">R</text>
        <line x1="50" y1="285" x2="90" y2="285" style="stroke:blue;stroke-width:3" /> 
        <text x="305" y="335" style="fill:green;font-size:28px;">(R)</text>
        <text x="270" y="365" style="fill:green;font-size:28px;">Resistance</text>
        <text x="390" y="295" style="fill:green;font-size:28px;">R=</text>
        <text x="440" y="280" style="fill:green;font-size:28px;">V</text>
        <text x="445" y="310" style="fill:green;font-size:28px;">I</text>
        <line x1="430" y1="285" x2="470" y2="285" style="stroke:green;stroke-width:3" />
        <text x="350" y="180" style="fill:black;font-size:28px;">V</text>
        <text x="348" y="210" style="fill:black;font-size:28px;">IR</text>
        <line x1="340" y1="185" x2="380" y2="185" style="stroke:black;stroke-width:3" />
        <text x="385" y="195" style="fill:black;font-size:28px;">=1</text>     
    </svg>            
</body>
</html>
to produce the Ohm's law triangle. Like this,
triangle.png

Interestingly, this produces a file a little over 1k. The same image saved as .png is 22k.

Hope this is helpful to someone.

Mike.
 

Attachments

  • mikes calculator.txt
    17.8 KB · Views: 15

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