31:T918,resistor_decades = { return { 40: [1.0, 2.2, 4.7], 20: [1.0, 1.5, 2.2, 3.3, 4.7, 6.8], 10: [1.0, 1.2, 1.5, 1.8, 2.2, 2.7, 3.3, 3.9, 4.7, 5.6, 6.8, 8.2], 5: [1.0, 1.1, 1.2, 1.3, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.7, 3.0, 3.3, 3.6, 3.9, 4.3, 4.7, 5.1, 5.6, 6.2, 6.8, 7.5, 8.2, 9.1], 2: [1.00, 1.05, 1.10, 1.15, 1.21, 1.27, 1.33, 1.40, 1.47, 1.54, 1.62, 1.69, 1.78, 1.87, 1.96, 2.05, 2.15, 2.26, 2.37, 2.49, 2.61, 2.74, 2.87, 3.01, 3.16, 3.32, 3.48, 3.65, 3.83, 4.02, 4.22, 4.42, 4.64, 4.87, 5.11, 5.36, 5.62, 5.90, 6.19, 6.49, 6.81, 7.15, 7.50, 7.87, 8.25, 8.66, 9.09, 9.53], 1: [1.00, 1.02, 1.05, 1.07, 1.10, 1.13, 1.15, 1.18, 1.21, 1.24, 1.27, 1.30, 1.33, 1.37, 1.40, 1.43, 1.47, 1.50, 1.54, 1.58, 1.62, 1.65, 1.69, 1.74, 1.78, 1.82, 1.87, 1.91, 1.96, 2.00, 2.05, 2.10, 2.15, 2.21, 2.26, 2.32, 2.37, 2.43, 2.49, 2.55, 2.61, 2.67, 2.74, 2.80, 2.87, 2.94, 3.01, 3.09, 3.16, 3.24, 3.32, 3.40, 3.48, 3.57, 3.65, 3.74, 3.83, 3.92, 4.02, 4.12, 4.22, 4.32, 4.42, 4.53, 4.64, 4.75, 4.87, 4.99, 5.11, 5.23, 5.36, 5.49, 5.62, 5.76, 5.90, 6.04, 6.19, 6.34, 6.49, 6.65, 6.81, 6.98, 7.15, 7.32, 7.50, 7.68, 7.87, 8.06, 8.25, 8.45, 8.66, 8.87, 9.09, 9.31, 9.53, 9.76], "<1": [1.00, 1.01, 1.02, 1.04, 1.05, 1.06, 1.07, 1.09, 1.10, 1.11, 1.13, 1.14, 1.15, 1.17, 1.18, 1.20, 1.21, 1.23, 1.24, 1.26, 1.27, 1.29, 1.30, 1.32, 1.33, 1.35, 1.37, 1.38, 1.40, 1.42, 1.43, 1.45, 1.47, 1.49, 1.50, 1.52, 1.54, 1.56, 1.58, 1.60, 1.62, 1.64, 1.65, 1.67, 1.69, 1.72, 1.74, 1.76, 1.78, 1.80, 1.82, 1.84, 1.87, 1.89, 1.91, 1.93, 1.96, 1.98, 2.00, 2.03, 2.05, 2.08, 2.10, 2.13, 2.15, 2.18, 2.21, 2.23, 2.26, 2.29, 2.32, 2.34, 2.37, 2.40, 2.43, 2.46, 2.49, 2.52, 2.55, 2.58, 2.61, 2.64, 2.67, 2.71, 2.74, 2.77, 2.80, 2.84, 2.87, 2.91, 2.94, 2.98, 3.01, 3.05, 3.09, 3.12, 3.16, 3.20, 3.24, 3.28, 3.32, 3.36, 3.40, 3.44, 3.48, 3.52, 3.57, 3.61, 3.65, 3.70, 3.74, 3.79, 3.83, 3.88, 3.92, 3.97, 4.02, 4.07, 4.12, 4.17, 4.22, 4.27, 4.32, 4.37, 4.42, 4.48, 4.53, 4.59, 4.64, 4.70, 4.75, 4.81, 4.87, 4.93, 4.99, 5.05, 5.11, 5.17, 5.23, 5.30, 5.36, 5.42, 5.49, 5.56, 5.62, 5.69, 5.76, 5.83, 5.90, 5.97, 6.04, 6.12, 6.19, 6.26, 6.34, 6.42, 6.49, 6.57, 6.65, 6.73, 6.81, 6.90, 6.98, 7.06, 7.15, 7.23, 7.32, 7.41, 7.50, 7.59, 7.68, 7.77, 7.87, 7.96, 8.06, 8.16, 8.25, 8.35, 8.45, 8.56, 8.66, 8.76, 8.87, 8.98, 9.09, 9.20, 9.31, 9.42, 9.53, 9.65, 9.76, 9.88] }} 32:T571,// Colors for a standard resistor function std_colors(std) { let decade = standard_decade(std.t) let colors = { "-3": d3.color("#FF69B4"), "-2": d3.color("#C0C0C0"), "-1": d3.color("#CFB53B"), "0": d3.color("#000000"), "1": d3.color("#964B00"), "2": d3.color("#FF0000"), "3": d3.color("#FFA500"), "4": d3.color("#FFFF00"), "5": d3.color("#9ACD32"), "6": d3.color("#6495ED"), "7": d3.color("#9400D3"), "8": d3.color("#A0A0A0"), "9": d3.color("#FFFFFF"), } let tol_colors = { "10": colors[-2], "5": colors[-1], "1": colors[1], "2": colors[2], "0.5": colors[5], "0.25": colors[6], "0.1": colors[7], "0.05": colors[3], "0.025": colors[4], "0.01": colors[8], } let idx1 = Math.floor(Math.round(std.m * 1000) / 1000) let idx2 = Math.floor(Math.round(std.m * 1000) / 100) % 10 let idx3 = Math.floor(Math.round(std.m * 1000) / 10) % 10 let idxe = Math.round(std.e) if (decade.length < 12) { // No tolerance band; 2 colors + multiplier return [colors[idx1], colors[idx2], colors[idxe]]; } else if (decade.length < 48) { // 2 colors + multiplier + tolerance return [colors[idx1], colors[idx2], colors[idxe], tol_colors[std.t]] } else { // 3 colors + multiplier + tolerance return [colors[idx1], colors[idx2], colors[idx3], colors[idxe], tol_colors[std.t]]; } } 33:[] 2f:{"title":"Standard resistor values","cells":[{"id":0,"value":"md`# Standard resistor values\n\nResistor values are [standardized by IEC 60063:2015](https://en.wikipedia.org/wiki/E_series_of_preferred_numbers). In short, given a resistor value tolerance (such as 10%), there is a standard set of nominal values that resistors are manufactured with. For example, there is no 3.0Ω resistor with 10% tolerance — you have to design with either a 2.7Ω resistor or with a 3.3Ω resistor (or use a resistor with 5% tolerance). \n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":10,"value":"md`\nResistor values often need to be chosen to meet some minimal or maximal value. You can use these functions to select the smallest or largest standard resistor value that meets your tolerance criteria. For example:\n`\n","pinned":false,"hidden":false,"mode":"ojs"},{"id":14,"value":"{\n let r = 1.25/950e-6\n let tol = 1\n let std = std_r(tol).above(r)\n return html`The smallest standard ${pct(tol)} resistor ≥ ${Ω(r)} is ${Ω(std)}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":54,"value":"{\n let r = 1.25/950e-6\n let tol = 10\n let std = std_r(tol).below(r)\n return html`The largest standard ${pct(tol)} resistor ≤ ${Ω(r)} is ${Ω(std)}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":421,"value":"md`You can check the \\`min\\` and \\`max\\` properties on the returned values to find out the range of resistances that a standard resistor covers:`","pinned":false,"hidden":false,"mode":"ojs"},{"id":434,"value":"{\n let r = 3\n let tol = 10\n let std = std_r(tol).below(r)\n return html`The largest standard ${pct(tol)} resistor ≤ ${Ω(r)} ranges from ${Ω(std.min.toFixed(3))} to ${Ω(std.max.toFixed(3))}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":224,"value":"md`Note that \\`above()\\` and \\`below()\\` will find the resistor that is *guaranteed* to be above/below the given value. For example, if you are looking for a resistor ≥ ${Ω(3.1)}, you can't use a ${Ω(3.3)} resistor, because it could fall anywhere between ${Ω(3.3)} – 10% = ${Ω(2.97)} and ${Ω(3.3)} + 10% = ${Ω(3.63)}, so it's not guaranteed to be ≥ ${Ω(3.1)}. The smallest resistor that meets that constraint is actually ${Ω(3.9)}:`","pinned":false,"hidden":false,"mode":"ojs"},{"id":227,"value":"{\n let r = 3.1\n let tol = 10\n return html`The smallest standard ${pct(tol)} resistor ≥ ${Ω(r)} is ${Ω(std_r(tol).above(r))}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":495,"value":"md`If you would like to find the first standard resistor above/below a certain value, and you are OK with it being a standard resistor whole tolerance range *includes* that value, you can use \\`aboveish()\\` and \\`belowish()\\`.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":406,"value":"{\n let r = 3.1\n let tol = 10\n let std = std_r(tol).aboveish(r)\n return html`The smallest standard ${pct(tol)} resistor approximately above ${Ω(r)} is ${Ω(std)}, and its range is ${Ω(std.min.toFixed(3))} – ${Ω(std.max.toFixed(3))}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":413,"value":"{\n let r = 3.1\n let tol = 10\n let std = std_r(tol).belowish(r)\n return html`The smallest standard ${pct(tol)} resistor approximately below ${Ω(r)} is ${Ω(std)}, and its range is ${Ω(std.min.toFixed(3))} – ${Ω(std.max.toFixed(3))}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":401,"value":"md` Although in theory adjacent standard ranges are always supposed to overlap, and therefore at least one of \\`aboveish()\\` and \\`belowish()\\` should contain the value you are looking for, in practice, they don't; for example, the standard ${Ω(2.4)} and ${Ω(2.7)} ${pct(5)} resistors leave a small gap between them. As a result, you cannot assume that the range of either \\`aboveish()\\` or \\`belowish()\\` will include the value:`","pinned":false,"hidden":false,"mode":"ojs"},{"id":487,"value":"{\n let r = 2.55\n let tol = 5\n let aboveish = std_r(tol).aboveish(r)\n let belowish = std_r(tol).belowish(r)\n\n return html`The smallest standard ${pct(tol)} resistor approximately above ${Ω(r)} is ${Ω(aboveish)} (${Ω(aboveish.min.toFixed(3))} – ${Ω(aboveish.max.toFixed(3))}), but the largest standard ${pct(tol)} resistor approximately below ${Ω(r)} is ${Ω(belowish)} (${Ω(belowish.min.toFixed(3))} – ${Ω(belowish.max.toFixed(3))}).`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":114,"value":"md`## Resistor color coding\n\nThrough-hole resistors use a [color code](https://en.wikipedia.org/wiki/Electronic_color_code) to indicate their value. You can show the bands in the standard order (most-significant-to-least-significant) for a standard resistor using the \\`bands\\` property:`","pinned":false,"hidden":false,"mode":"ojs"},{"id":145,"value":"{\n let r = 2.9\n let tol = 10\n let std_above = std_r(tol).above(r)\n return html`The smallest standard ${pct(tol)} resistor ≥ ${Ω(r)} is ${Ω(std_above)} and looks like ${std_above.bands}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":187,"value":"{\n let r = 194000\n let tol = 1\n let std_above = std_r(tol).above(r)\n return html`The smallest standard ${pct(tol)} resistor ≥ ${Ω(r)} is ${Ω(std_above)} and looks like ${std_above.bands}`\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":521,"value":"md`If you just want the list of colors, use the \\`colors\\` property:`","pinned":false,"hidden":false,"mode":"ojs"},{"id":121,"value":"std_r(10).above(3.3).colors","pinned":true,"hidden":false,"mode":"ojs"},{"id":90,"value":"html`

`","pinned":false,"hidden":false,"mode":"ojs"},{"id":275,"value":"md`## API`","pinned":false,"hidden":false,"mode":"ojs"},{"id":13,"value":"function std_r(tolerance) {\n return {\n above: function(r) {\n return num_with_colors(find_above(r, tolerance));\n },\n below: function(r) {\n return num_with_colors(find_below(r, tolerance));\n },\n aboveish: function(r) {\n let std = find_std(r, standard_decade(tolerance))\n return num_with_colors(values(std.aboveish, tolerance));\n },\n belowish: function(r) {\n let std = find_std(r, standard_decade(tolerance))\n return num_with_colors(values(std.belowish, tolerance));\n },\n exact: function(r) {\n let std = find_below(r, tolerance)\n if (std.belowish != std.aboveish) {\n return undefined;\n } else {\n return num_with_colors(std.belowish);\n }\n }\n }\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":271,"value":"md`## Internals`","pinned":false,"hidden":false,"mode":"ojs"},{"id":251,"value":"$31","pinned":false,"hidden":false,"mode":"ojs"},{"id":265,"value":"function standard_decade(tolerance) {\n return tolerance >= 1 ? resistor_decades[tolerance] : resistor_decades[\"<1\"];\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":264,"value":" // Decompose r into exponent and mantissa and find the standard values immediately above and below\nfunction find_std(r, decade) {\n let e = Math.floor(Math.log10(r));\n let m = r / Math.pow(10, e);\n\n // Binary search in decade for values closest to r\n let imin = 0;\n let imax = decade.length;\n while (imin + 1 < imax) {\n let imid = Math.floor((imin + imax) / 2);\n let rmid = decade[imid];\n if (m == rmid) {\n imax = imid;\n imin = imid;\n break;\n } else if (m < rmid) {\n imax = imid;\n } else {\n imin = imid;\n }\n }\n \n return {\n r: {\n m: m, \n e: e\n }, \n belowish: {\n idx: imin,\n m: decade[imin],\n e: e\n },\n aboveish: {\n // Overflow into next decade if needed\n idx: imax == decade.length ? 1 : imax,\n m: imax == decade.length ? 1 : decade[imax],\n e: imax == decade.length ? e + 1 : e\n }\n }\n}\n","pinned":false,"hidden":false,"mode":"ojs"},{"id":278,"value":"// Find standard value above r\nfunction find_above(r, tolerance) {\n let decade = standard_decade(tolerance)\n let std = find_std(r, decade).aboveish\n // Check that std is strictly ≥ r throughout its tolerance range\n if (std.m * Math.pow(10, std.e) * (1 - tolerance / 100) < r) {\n if (std.idx < decade.length - 1) {\n std.idx += 1\n } else {\n std.idx = 0\n std.e += 1\n }\n std.m = decade[std.idx]\n }\n return values(std, tolerance)\n}\n\n\n","pinned":false,"hidden":false,"mode":"ojs"},{"id":284,"value":"// Find standard value below r\nfunction find_below(r, tolerance) {\n let decade = standard_decade(tolerance)\n let std = find_std(r, decade).belowish\n // Check that std is strictly ≤ r throughout its tolerance range\n if (std.m * Math.pow(10, std.e) * (1 + tolerance / 100) > r) {\n if (std.idx > 0) {\n std.idx -= 1\n } else {\n std.idx = decade.length - 1\n std.e -= 1\n }\n std.m = decade[std.idx]\n }\n return values(std, tolerance)\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":430,"value":"function values(std, tolerance) {\n let r = std.m * Math.pow(10, std.e)\n return {\n r: r,\n m: std.m,\n e: std.e,\n t: tolerance,\n min: r * (1 - tolerance / 100),\n max: r * (1 + tolerance / 100)\n }\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":287,"value":"$32","pinned":false,"hidden":false,"mode":"ojs"},{"id":609,"value":"viewof r_bg_brown = colorPicker(\"#c77a16\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":600,"value":"viewof r_bg_blue = colorPicker(\"#67b2bf\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":292,"value":"// Attach attributes to a resistor number\nfunction num_with_colors(std) {\n let num = new Number(std.m * Math.pow(10, std.e));\n num.colors = std_colors(std);\n Object.defineProperty(num, \"bands\", {\n get: function () {\n return bands(this.colors);\n }\n });\n num.e = std.e;\n num.m = std.m;\n num.t = std.t;\n num.min = std.min;\n num.max = std.max;\n return num;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":303,"value":"md`## Tests`","pinned":false,"hidden":false,"mode":"ojs"},{"id":579,"value":"md`These are all the band colors on two different backgrounds. Use the color pickers above to adjust the backgrounds if necessary.\n\n * ${std_r(5).aboveish(0.99e-3).bands} ${Ω(std_r(5).aboveish(0.99e-3).toFixed(4))} \n * ${std_r(5).aboveish(2.4e-2).bands} ${Ω(std_r(5).aboveish(2.4e-2).toFixed(4))}\n * ${std_r(5).aboveish(3.6e8).bands} ${Ω(std_r(5).aboveish(3.6e8))}\n * ${std_r(5).aboveish(7.5e9).bands} ${Ω(std_r(5).aboveish(7.5e9))}\n * ${std_r(1).aboveish(3.09e-1).bands} ${Ω(std_r(1).aboveish(3.09e-1).toFixed(4))} \n * ${std_r(2).aboveish(4.87e-2).bands} ${Ω(std_r(2).aboveish(4.87e-2).toFixed(5))}\n * ${std_r(0.5).aboveish(6.65e-3).bands} ${Ω(std_r(0.5).aboveish(6.65e-3).toFixed(6))}\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":306,"value":"standard_decade(10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":308,"value":"find_std(3, standard_decade(10))","pinned":true,"hidden":false,"mode":"ojs"},{"id":318,"value":"find_above(3, 10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":320,"value":"find_below(3, 10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":324,"value":"find_above(7, 10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":363,"value":"find_above(8.5, 10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":326,"value":"find_below(1.1, 10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":328,"value":"find_above(3.2, 10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":330,"value":"find_below(2.8, 10)","pinned":true,"hidden":false,"mode":"ojs"},{"id":590,"value":"std_r(5).aboveish(1.0)","pinned":true,"hidden":false,"mode":"ojs"},{"id":293,"value":"// Color bands\nfunction bands(colors) {\n return html` 4 ? 'blue' : 'brown'}\">${colors.map(c => `

`)}`;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":599,"value":"import {colorPicker} from \"@shaunlebron/color-picker\"\n","pinned":false,"hidden":false,"mode":"ojs"},{"id":94,"value":"import { Ω, pct } from \"@airbornemint/units\"","pinned":false,"hidden":false,"mode":"ojs"},{"id":129,"value":"d3 = require(\"d3@5\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":471,"value":"html``","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W33","stdlib":"1","titling":"auto"}