PHP code to calculate the resistance value of a resistor based on its color bands

Here's an example PHP code to calculate the resistance value of a resistor based on its color bands:

<?php

$color_codes = [
    'black' => 0,
    'brown' => 1,
    'red' => 2,
    'orange' => 3,
    'yellow' => 4,
    'green' => 5,
    'blue' => 6,
    'violet' => 7,
    'gray' => 8,
    'white' => 9
];

$first_band = 'brown'; // replace with the actual color of the first band
$second_band = 'black'; // replace with the actual color of the second band
$third_band = 'red'; // replace with the actual color of the third band

$multiplier = 1;
$tolerance = 0.05;

$first_digit = $color_codes[$first_band];
$second_digit = $color_codes[$second_band];
$third_digit = $color_codes[$third_band];

$ohms = ($first_digit * 10 + $second_digit) * $multiplier;
$ohms_string = number_format($ohms, 2);

echo "Resistance value: {$ohms_string} ohms (+/-{$tolerance})";

?>