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| function Resistor() {
this.smtCode = null;
this.value = 0;
this.scaledUnit = null;
this.scaledValue = 0;
this.tolerance = 0;
this.tempCoefficient = 0;
this.bands = new Array();
var that = this;
var colorMap = {
black: {color: "black", value: 0, multiplier: 1, tolerance: null, tempCoefficient: null},
brown: {color: "brown", value: 1, multiplier: 1e1, tolerance: 1, tempCoefficient: 100},
red: {color: "red", value: 2, multiplier: 1e2, tolerance: 2, tempCoefficient: 50},
orange: {color: "orange", value: 3, multiplier: 1e3, tolerance: null, tempCoefficient: 15},
yellow: {color: "yellow", value: 4, multiplier: 1e4, tolerance: null, tempCoefficient: 25},
green: {color: "green", value: 5, multiplier: 1e5, tolerance: 0.5, tempCoefficient: null},
blue: {color: "blue", value: 6, multiplier: 1e6, tolerance: 0.25, tempCoefficient: null},
violet: {color: "violet", value: 7, multiplier: 1e7, tolerance: 0.1, tempCoefficient: null},
gray: {color: "gray", value: 8, multiplier: 1e8, tolerance: 0.05, tempCoefficient: null},
white: {color: "white", value: 9, multiplier: 1e9, tolerance: null, tempCoefficient: null},
gold: {color: "gold", value: null, multiplier: 1e-1, tolerance: 5, tempCoefficient: null},
silver: {color: "silver", value: null, multiplier: 1e-2, tolerance: 10, tempCoefficient: null},
none: {color: "none", value: null, multiplier: 1, tolerance: 20, tempCoefficient: null}
};
var unitMap = new Array("pΩ", "nΩ", "µΩ", "mΩ", "Ω", "kΩ", "MΩ", "GΩ", "TΩ");
this.setColorBands = function(colors) {
for (index in colors) {
if (typeof colorMap[colors[index]] != "undefined") {
this.bands.push(colorMap[colors[index]]);
}
}
}
this.setSmtCode = function(code) {
this.smtCode = String(code);
}
this.setValue = function(value) {
this.value = Number(value);
this.scaledUnit = calculateScaledUnit(this.value);
this.scaledValue = calculateScaledValue(this.value);
}
this.calculate = function() {
if (!this.value > 0) {
this.setValue(calculateValue());
}
if (this.smtCode == null) {
this.setSmtCode(calculateSmtCode(this.value));
}
if (!this.bands.length > 0) {
this.setColorBands(calculateBands(this.value));
}
if (this.bands.length > 4) {
this.tolerance = this.bands[4].tolerance;
if (this.bands.length == 6) {
this.tempCoefficient = this.bands[5].tempCoefficient;
}
}
}
this.toString = function() {
var string = "Value: " + this.scaledValue + this.scaledUnit + " - ";
string += "Colours: ";
for (i in this.bands) {
string += this.bands[i].color + ", ";
}
string = string.slice(0, -2) + " - ";
string += "SMT Code: " + this.smtCode + " - ";
string += "Tolerance: " + (this.tolerance == 0 ? "Unknown" : this.tolerance + "%") + " - ";
string += "Temperature Coefficient: " + (this.tempCoefficient == 0 ? "Unknown" : this.tempCoefficient + "ppm");
return string;
}
var calculateValue = function() {
if (that.bands.length > 3) {
return calculateValueViaBands(that.bands);
}
if (that.smtCode != null) {
return calculateValueViaSmtCode(that.smtCode);
}
return false;
}
var calculateValueViaBands = function(bands) {
var value = String(bands[0].value) + String(bands[1].value);
var multiplier = bands[2].multiplier;
if (bands.length > 4) {
value += String(bands[2].value);
multiplier = bands[3].multiplier;
}
return Number(value) * multiplier;
}
var calculateValueViaSmtCode = function(smtCode) {
var value;
if (smtCode.indexOf("R") > -1) {
value = smtCode.replace(/R/i, ".");
} else {
var multiplier = 1;
switch (smtCode.length) {
case 2:
value = smtCode;
break;
case 3:
value = smtCode.substring(0, 2);
multiplier = smtCode.substring(2);
break;
case 4:
value = smtCode.substring(0, 3);
multiplier = smtCode.substring(3);
break
default:
return false;
}
value = Number(value) * Math.pow(10, Number(multiplier));
}
return value;
}
var calculateBands = function(value) {
var multiplier = Math.pow(10, String(value).length - 2);
var values = String(value / multiplier).split("");
var result = new Array();
for (i in colorMap) {
if (colorMap[i].multiplier == multiplier) {
multiplier = i;
break;
}
}
for (i in values) {
for (j in colorMap) {
if (colorMap[j].value == Number(values[i])) {
result.push(j);
}
}
}
result.push(multiplier);
return result;
}
var calculateSmtCode = function(value) {
var indeces = calculateBands(value);
var multiplier = indeces.pop();
var lastDigit = (Math.log(colorMap[multiplier].multiplier) / Math.LN10);
if (lastDigit > 9) {
return false;
}
var code = "";
for (i in indeces) {
code += colorMap[indeces[i]].value;
}
return code + lastDigit;
}
var calculateScaledValue = function(value) {
return value/Math.pow(1000, getExponent(value));
}
var calculateScaledUnit = function(value) {
if (value == 0) {
return "Ω";
}
var unit = unitMap[getExponent(value) + 4];
if (typeof unit == "undefined") {
return false;
}
return unit;
}
var getExponent = function(value) {
return Math.floor(Math.log(value) / Math.log(1000));
}
} |