vk3cpu/inductor_swg.html

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>VK3CPU RF Inductor Calculator</title>
<link rel="stylesheet" href="inductor.css">
</head>
<body>
<header>Miguel <a href="mailto:vk3cpu@gmail.com">VK3CPU</a> - RF Inductor Calculator<br><a href="inductor.html">[Wire Metric]</a> <a href="inductor_imp.html">[Wire AWG]</a> <a href="inductor_lrg.html">[Coax Metric]</a></header>
<section class="gridLayoutClass">
<div id="inductor-container" class="inductor-container" style="position: relative;">
<canvas id="inductor2D" class="inductorClass" width="350" height="350">
</canvas>
</div>
<div class="slider_container">
<div class="sliders">
<label for="conductor_diameter_slider">&#8960a:</label>
<input type="range" id="conductor_diameter_slider" min="0" max="50" value="29" step="1">
</div>
<div class="sliders">
<label for="loop_diameter_slider">&#8960b:</label>
<input type="range" id="loop_diameter_slider" min="0.20" max="4.0" value="1.00" step="0.01">
</div>
<div class="sliders">
<label for="loop_spacing_slider">c/a:</label>
<input type="range" id="loop_spacing_slider" min="1.1" max="4.0" value="2.0" step="0.01">
</div>
<div class="sliders">
<label for="loop_turns_slider">N:</label>
<input type="range" id="loop_turns_slider" min="2" max="150" value="8.0" step="1.0">
</div>
<div class="sliders">
<label for="frequency_slider">f:</label>
<input type="range" id="frequency_slider" min="1.0" max="54.0" value="7.0" step="0.05">
</div>
</div>
<div id="notes" class="notes">
<br>
<b><u>Notes:</u></b><br>
RF Inductor Calculator was developed to help users predict the RF characteristics of a single-layer solenoid-style air-core inductor. <br><br>
<u>Inputs via the slider widgets:</u>
<ul>
<li>&#8960;a : Conductor diameter slider changes SWG from 0-50. Actual diameter displayed in decimal inches.</li>
<li>&#8960;b : Coil diameter in decimal inches.</li>
<li>c/a : 'c' is the winding-to-winding distance, measured from the conductor mid-points. The 'a' is the conductor diameter, so 'c/a' is the spacing ratio. (c/a >= 1.1)
A low-value will increase the resistance due to the proximity effect.</li>
<li>N : Number of turns or windings.</li>
<li>f : The frequency of interest (MHz) for some of the calculations. Frequency dependent results are shown on the top-right.</li>
</ul>
<p>Characteristics on the left are independent of frequency, while the characteristics on the right are dependent on the selected frequency. <br><br>
Each of the graphic representations attempt to keep the relative geometry correct, without exceeding the drawing boundary. The coil diameter
relative to the conductor diameter are representative. </p>
<u>Calculated dimensions:</u>
<ul>
<li>&#8960;o : Outer coil diameter (inches) </li>
<li>&#8960;i : Inner coil diameter (inches) - corresponds to the diameter of the winding former.</li>
<li>c : Distance between windings, measured from the conductor centers (inches).</li>
<li>&#8467; : Length of the coil (inches). Equal to c x N.</li>
</ul>
<u>Calculated parameters:</u>
<ul> <b>Frequency independent:[L]</b>
<li>L : Inductance is calculated using Nagaoka's equation incorporating his coefficient.</li>
<li>C : Capacitance is calculated using Knight's 2016 paper on self-resonance and self-capacitance of solenoid coils.</li>
<li>Rdc : DC resistance is calculated using conductor length divided by the conductor cross-sectional area, assuming a copper conductor.</li>
<li>SRF : Self-resonant frequency (MHz) for the unloaded coil. </li>
<li>wire : Length of wire required to wind the inductor. </li>
</ul>
<ul> <b>Frequency dependent:[R]</b> (Text goes <font color="red">RED</font> when selected frequency > SRF. Inductor model is not accurate once SRF is exceeded.)
<li>f : Selected frequency in MHz</li>
<li>&#948; : Skin depth due to skin effect (&#956;m)</li>
<li>Rac : AC resistance is calculated using the skin effect and proximity resistance from empirical data collected by Medhurst using the spacing ratio, and length-to-diameter ratio.</li>
<li>X&#8343; : Inductive reactance at the given frequency. (&#937;) - pure inductive component, ignoring parasitic capacitance </li>
<li>Z : Complex impedance at the given frequency. (&#937;) - includes losses due to series Rac and parallel parasitic C</li>
<li>|Z| : Impedance magnitude at the given frequency. (&#937;)</li>
<li>Q : Effective Quality Factor of the inductor at the given frequency. - (|Z.im|/Z.re)</li>
</ul>
</div>
</section>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mathjs/7.5.1/math.min.js"></script>
<script src="inductor.js"></script>
<script>
function swgToMm(swg) {
//
switch (swg) {
case 50: return 0.0254;
case 49: return 0.0305;
case 48: return 0.0406;
case 47: return 0.0508;
case 46: return 0.0610;
case 45: return 0.0711;
case 44: return 0.0813;
case 43: return 0.0914;
case 42: return 0.1016;
case 41: return 0.1118;
case 40: return 0.1219;
case 39: return 0.1321;
case 38: return 0.1524;
case 37: return 0.1727;
case 36: return 0.1930;
case 35: return 0.2134;
case 34: return 0.2337;
case 33: return 0.2540;
case 32: return 0.2743;
case 31: return 0.2946;
case 30: return 0.3150;
case 29: return 0.3454;
case 28: return 0.3759;
case 27: return 0.4166;
case 26: return 0.4572;
case 25: return 0.508;
case 24: return 0.559;
case 23: return 0.610;
case 22: return 0.711;
case 21: return 0.813;
case 20: return 0.914;
case 19: return 1.016;
case 18: return 1.219;
case 17: return 1.422;
case 16: return 1.626;
case 15: return 1.829;
case 14: return 2.032;
case 13: return 2.337;
case 12: return 2.642;
case 11: return 2.946;
case 10: return 3.251;
case 9: return 3.658;
case 8: return 4.064;
case 7: return 4.470;
case 6: return 4.877;
case 5: return 5.385;
case 4: return 5.893;
case 3: return 6.401;
case 2: return 7.010;
case 1: return 7.620;
case 0: return 8.230;
default: return 0.0;
}
}
// Define global storage for calculated values, so we don't recalculate the same things multiple times:
var inductor = {
loop_diameter_meters : 0.0,
cond_diameter_meters : 0.0,
spacing_ratio : 0.0,
loop_turns : 0.0,
frequency_hz : 0.0,
L : 0.0,
C : 0.0,
Rdc : 0.0,
SRF : 0.0,
Xl : 0.0,
Xc : 0.0,
Z : 0.0,
skin_depth : 0.0,
Rac : 0.0,
Q : 0.0
};
// Solve all the parameters, and re-draw the canvas:
function recalculate() {
// Input variables:
inductor.loop_diameter_meters = 0.001 * loop_diameter_slider.value * 25.4; // Inches to mm then to m
inductor.cond_diameter_meters = 0.001 * swgToMm(50.0 - conductor_diameter_slider.value);
inductor.spacing_ratio = 1.0 * loop_spacing_slider.value;
inductor.loop_turns = 1.0 * loop_turns_slider.value;
inductor.frequency_hz = 1e6 * frequency_slider.value;
// Frequency independent characteristics:
inductor.L = getInductance(inductor.loop_diameter_meters, inductor.cond_diameter_meters, inductor.spacing_ratio, inductor.loop_turns);
inductor.C = multiloopCapacitance(inductor.loop_diameter_meters, inductor.cond_diameter_meters, inductor.spacing_ratio, inductor.loop_turns);
inductor.Rdc = dcResistance(inductor.loop_diameter_meters, inductor.cond_diameter_meters, inductor.spacing_ratio, inductor.loop_turns);
inductor.SRF = selfResonantFrequency(inductor.L, inductor.C);
// Frequency dependent characteristics:
inductor.Xl = inductiveReactance(inductor.frequency_hz, inductor.L);
inductor.Xc = capacitiveReactance(inductor.frequency_hz, inductor.C);
inductor.skin_depth = skinDepth(inductor.frequency_hz);
inductor.Rac = acResistance(inductor.loop_diameter_meters, inductor.cond_diameter_meters, inductor.spacing_ratio, inductor.loop_turns, inductor.frequency_hz);
//inductor.Q = qualityFactor(inductor.Xl, inductor.Rac);
// Calculate impedance:
var Zl = math.complex(inductor.Rac, inductor.Xl);
var Zc = math.complex(0, inductor.Xc);
inductor.Z = math.divide(math.multiply(Zl, Zc), math.add(Zl, Zc));
inductor.Q = Math.abs(inductor.Z.im) / inductor.Z.re;
// Redraw the canvas:
//drawDesign();
}
// Specify fonts for changing parameters controlled by the sliders:
var normal_font = "12px arial";
var emphasis_font = "bold 14px arial";
const emphasis_delay = 1200;
var loop_dia_timer_handler = 0;
var loop_dia_font = normal_font;
loop_diameter_slider.oninput = function() {
recalculate();
if(loop_dia_timer_handler == 0) {
loop_dia_font = emphasis_font;
loop_dia_timer_handler = setTimeout(function(){
loop_dia_font = normal_font;
drawDesign();
loop_dia_timer_handler = 0;
}, emphasis_delay);
} else {
clearTimeout(loop_dia_timer_handler);
loop_dia_timer_handler = setTimeout(function(){
loop_dia_font = normal_font;
drawDesign();
loop_dia_timer_handler = 0;
}, emphasis_delay);
}
drawDesign();
}
var cond_dia_timer_handler = 0;
var cond_dia_font = normal_font;
conductor_diameter_slider.oninput = function() {
recalculate();
if(cond_dia_timer_handler == 0) {
cond_dia_font = emphasis_font;
cond_dia_timer_handler = setTimeout(function(){
cond_dia_font = normal_font;
drawDesign();
cond_dia_timer_handler = 0;
}, emphasis_delay);
} else {
clearTimeout(cond_dia_timer_handler);
cond_dia_timer_handler = setTimeout(function(){
cond_dia_font = normal_font;
drawDesign();
cond_dia_timer_handler = 0;
}, emphasis_delay);
}
drawDesign();
}
var turns_timer_handler = 0;
var turns_font = normal_font;
loop_turns_slider.oninput = function() {
recalculate();
if(turns_timer_handler == 0) {
turns_font = emphasis_font;
turns_timer_handler = setTimeout(function(){
turns_font = normal_font;
drawDesign();
turns_timer_handler = 0;
}, emphasis_delay);
} else {
clearTimeout(turns_timer_handler);
turns_timer_handler = setTimeout(function(){
turns_font = normal_font;
drawDesign();
turns_timer_handler = 0;
}, emphasis_delay);
}
drawDesign();
}
var spacing_timer_handler = 0;
var spacing_font = normal_font;
loop_spacing_slider.oninput = function() {
recalculate();
if(spacing_timer_handler == 0) {
spacing_font = emphasis_font;
spacing_timer_handler = setTimeout(function(){
spacing_font = normal_font;
drawDesign();
spacing_timer_handler = 0;
}, emphasis_delay);
} else {
clearTimeout(spacing_timer_handler);
spacing_timer_handler = setTimeout(function(){
spacing_font = normal_font;
drawDesign();
spacing_timer_handler = 0;
}, emphasis_delay);
}
drawDesign();
}
var frequency_timer_handler = 0;
var frequency_font = normal_font;
frequency_slider.oninput = function() {
recalculate();
if(frequency_timer_handler == 0) {
frequency_font = emphasis_font;
frequency_timer_handler = setTimeout(function(){
frequency_font = normal_font;
drawDesign();
frequency_timer_handler = 0;
}, emphasis_delay);
} else {
clearTimeout(frequency_timer_handler);
frequency_timer_handler = setTimeout(function(){
frequency_font = normal_font;
drawDesign();
frequency_timer_handler = 0;
}, emphasis_delay);
}
drawDesign();
}
window.onresize = function() {
recalculate();
drawDesign();
}
window.onorientationchange = function() {
recalculate();
drawDesign();
}
window.onbeforeprint = function() {
console.log("onbeforeprint");
drawDesign();
}
const afront_canvas = document.getElementById("inductor2D");
const fctx = afront_canvas.getContext('2d');
function drawDesign() {
const win_width = document.getElementById("inductor-container").clientWidth;
const win_height = document.getElementById("inductor-container").clientHeight;
afront_canvas.width = win_width-12;
afront_canvas.height = win_height-12;
fctx.clearRect(0, 0, win_width, win_height);
const loop_radius = 0.11 * win_height;
var cond_radius = loop_radius * (inductor.cond_diameter_meters / inductor.loop_diameter_meters);
const loopx = win_width/2;
const loopy = win_height/4;
const loop_diameter_mm = inductor.loop_diameter_meters * 1000.0;
const cond_diameter_mm = inductor.cond_diameter_meters * 1000.0;
const loop_diameter_inches = loop_diameter_mm / 25.4;
const cond_diameter_inches = cond_diameter_mm / 25.4;
fctx.font = "bold 14px arial";
fctx.textAlign = "center";
fctx.fillText("Wire - SWG", win_width*0.5, 18);
// Draw loop ends first, then draw the loop after:
fctx.strokeStyle = "grey";
fctx.beginPath();
fctx.arc(loopx - 0.5*loop_radius, loopy + 1.414*loop_radius, 0.5 * loop_radius, 0.0, -0.40 * Math.PI, true);
fctx.lineWidth = cond_radius * 2.0;
fctx.stroke();
fctx.strokeStyle = "black";
fctx.beginPath();
fctx.arc(loopx + 0.5*loop_radius, loopy + 1.414*loop_radius, 0.5 * loop_radius, Math.PI, -0.60 * Math.PI, false);
fctx.lineWidth = cond_radius * 2.0;
fctx.stroke();
// Draw loop:
fctx.beginPath();
fctx.arc(loopx, loopy, loop_radius, 0.0, 2.0 * Math.PI, false);
fctx.stroke();
fctx.lineWidth = 1.0;
// Draw loop diameter arrow:
const y_offset = loopy + loop_radius + 20;
var arrow_size = 10.0;
fctx.beginPath();
fctx.moveTo(loopx - loop_radius, loopy);
fctx.lineTo(loopx - loop_radius, y_offset);
fctx.lineTo(loopx - loop_radius - arrow_size, y_offset - arrow_size);
fctx.lineTo(loopx - loop_radius - arrow_size, y_offset + arrow_size);
fctx.lineTo(loopx - loop_radius, y_offset);
fctx.lineTo(loopx - loop_radius - 3.0*arrow_size, y_offset);
fctx.stroke();
fctx.beginPath();
fctx.moveTo(loopx + loop_radius, loopy);
fctx.lineTo(loopx + loop_radius, y_offset);
fctx.lineTo(loopx + loop_radius + arrow_size, y_offset - arrow_size);
fctx.lineTo(loopx + loop_radius + arrow_size, y_offset + arrow_size);
fctx.lineTo(loopx + loop_radius, y_offset);
fctx.lineTo(loopx + loop_radius + 3.0*arrow_size, y_offset);
fctx.stroke();
// Write conductor diameter symbol:
fctx.font = cond_dia_font;
fctx.textAlign = "right";
fctx.fillText("\u2300a = " + cond_diameter_inches.toFixed(4).toString() + "\"", loopx - loop_radius - 2.0*arrow_size, loopy - 6);
fctx.fillText("(" + cond_diameter_mm.toFixed(3).toString() + "mm)", loopx - loop_radius - 2.0*arrow_size, loopy + 12);
fctx.textAlign = "center";
//fctx.font = "14px courier";
fctx.fillText((50-conductor_diameter_slider.value).toString() + "SWG", loopx, loopy + 3);
//fctx.font = "12px arial";
fctx.textAlign = "right";
fctx.font = loop_dia_font;
// Write loop diameter symbol:
fctx.fillText("\u2300b = " + loop_diameter_inches.toFixed(2).toString() + "\"", loopx - loop_radius - 2.0*arrow_size, y_offset - 4);
fctx.fillText("(" + loop_diameter_mm.toFixed(2).toString() + "mm)", loopx - loop_radius - 2.0*arrow_size, y_offset + 12);
fctx.font = "12px arial";
fctx.fillText("(A=" + (cond_diameter_mm**2).toFixed(2).toString() + " mm\u00B2)", loopx - loop_radius - 2.0*arrow_size, loopy + 28);
// Draw inner-diameter arrows: (for using a winding former)
const inner_dia_y = loopy + loop_radius + 40;
fctx.beginPath();
fctx.moveTo(loopx - loop_radius + cond_radius, loopy);
fctx.lineTo(loopx - loop_radius + cond_radius, inner_dia_y);
fctx.lineTo(loopx - loop_radius + cond_radius - arrow_size, inner_dia_y - arrow_size);
fctx.lineTo(loopx - loop_radius + cond_radius - arrow_size, inner_dia_y + arrow_size);
fctx.lineTo(loopx - loop_radius + cond_radius, inner_dia_y);
fctx.lineTo(loopx - loop_radius - 3.0*arrow_size, inner_dia_y);
fctx.stroke();
fctx.beginPath();
fctx.moveTo(loopx + loop_radius - cond_radius, loopy);
fctx.lineTo(loopx + loop_radius - cond_radius, inner_dia_y);
fctx.lineTo(loopx + loop_radius - cond_radius + arrow_size, inner_dia_y - arrow_size);
fctx.lineTo(loopx + loop_radius - cond_radius + arrow_size, inner_dia_y + arrow_size);
fctx.lineTo(loopx + loop_radius - cond_radius, inner_dia_y);
fctx.lineTo(loopx + loop_radius + 3.0*arrow_size, inner_dia_y);
fctx.stroke();
fctx.textAlign = "left";
fctx.fillText("\u2300i = " + (loop_diameter_inches-0.5*cond_diameter_inches).toFixed(3).toString() + "\"", loopx + loop_radius + 2.0*arrow_size, inner_dia_y - 4);
fctx.fillText("(" + (loop_diameter_mm-0.5*cond_diameter_mm).toFixed(2).toString() + "mm)", loopx + loop_radius + 2.0*arrow_size, inner_dia_y + 12);
// Draw outer-diameter arrows: (for using a winding former)
const outer_dia_y = loopy + loop_radius + 0;
fctx.beginPath();
fctx.moveTo(loopx - loop_radius - cond_radius, loopy);
fctx.lineTo(loopx - loop_radius - cond_radius, outer_dia_y);
fctx.lineTo(loopx - loop_radius - cond_radius - arrow_size, outer_dia_y - arrow_size);
fctx.lineTo(loopx - loop_radius - cond_radius - arrow_size, outer_dia_y + arrow_size);
fctx.lineTo(loopx - loop_radius - cond_radius, outer_dia_y);
fctx.lineTo(loopx - loop_radius - 3.0*arrow_size, outer_dia_y);
fctx.stroke();
fctx.beginPath();
fctx.moveTo(loopx + loop_radius + cond_radius, loopy);
fctx.lineTo(loopx + loop_radius + cond_radius, outer_dia_y);
fctx.lineTo(loopx + loop_radius + cond_radius + arrow_size, outer_dia_y - arrow_size);
fctx.lineTo(loopx + loop_radius + cond_radius + arrow_size, outer_dia_y + arrow_size);
fctx.lineTo(loopx + loop_radius + cond_radius, outer_dia_y);
fctx.lineTo(loopx + loop_radius + 3.0*arrow_size, outer_dia_y);
fctx.stroke();
fctx.fillText("\u2300o = " + (loop_diameter_inches+0.5*cond_diameter_inches).toFixed(3).toString() + "\"", loopx + loop_radius + 2.0*arrow_size, outer_dia_y - 4);
fctx.fillText("(" + (loop_diameter_mm+0.5*cond_diameter_mm).toFixed(2).toString() + "mm)", loopx + loop_radius + 2.0*arrow_size, outer_dia_y + 12);
// Write loop inductance:
fctx.font = "12px arial";
fctx.textAlign = "left";
const L = inductor.L * 1.0e+6;
fctx.fillText("L = " + L.toPrecision(3).toString() + " \u03bcH", 8, 18);
fctx.fillText("C = " + (inductor.C * 1e12).toFixed(1) + " pF", 8, 32);
fctx.fillText("Rdc = " + inductor.Rdc.toFixed(2) + " \u03A9", 8, 46);
fctx.fillText("SRF = " + (inductor.SRF * 1e-6).toFixed(1) + " MHz", 8, 60);
const wire_length_m = Math.sqrt((inductor.loop_turns * inductor.spacing_ratio * inductor.cond_diameter_meters)**2 + (Math.PI * inductor.loop_diameter_meters * inductor.loop_turns)**2);
fctx.fillText("wire = " + (wire_length_m*3.2808).toFixed(2) + "\' (" + wire_length_m.toFixed(2) + "m)", 8, 74);
// Draw conductor diameter arrow:
fctx.beginPath();
fctx.moveTo(loopx - loop_radius - cond_radius, loopy);
fctx.lineTo(loopx - loop_radius - cond_radius - arrow_size, loopy - arrow_size);
fctx.lineTo(loopx - loop_radius - cond_radius - arrow_size, loopy + arrow_size);
fctx.lineTo(loopx - loop_radius - cond_radius, loopy);
fctx.lineTo(loopx - loop_radius - 3.0*arrow_size, loopy);
fctx.stroke();
fctx.beginPath();
fctx.moveTo(loopx - loop_radius + cond_radius, loopy);
fctx.lineTo(loopx - loop_radius + cond_radius + arrow_size, loopy - arrow_size);
fctx.lineTo(loopx - loop_radius + cond_radius + arrow_size, loopy + arrow_size);
fctx.lineTo(loopx - loop_radius + cond_radius, loopy);
fctx.lineTo(loopx - loop_radius + cond_radius + 2.0*arrow_size, loopy);
fctx.stroke();
//fctx.textAlign = "center";
//fctx.font = "14px courier";
//fctx.fillText((50-conductor_diameter_slider.value).toString() + "SWG", loopx, loopy - 6);
//fctx.font = "12px arial";
var cond_spacing = 2.0 * cond_radius * inductor.spacing_ratio;
if((cond_spacing * inductor.loop_turns) > (0.8 * win_width)) {
cond_radius = ((0.8 * win_width) / (inductor.loop_turns * 2.0*inductor.spacing_ratio));
cond_spacing = 2.0 * cond_radius * inductor.spacing_ratio;
}
var start_x = win_width/2.0 - inductor.loop_turns * cond_spacing * 0.5;
var top_y = win_height * 0.56;
var bot_y = top_y + 2.0 * cond_radius * (inductor.loop_diameter_meters / inductor.cond_diameter_meters);
var angle = math.atan2((cond_spacing * 0.5), (bot_y - top_y));
for (let i = 0; i < inductor.loop_turns; i++) {
fctx.beginPath();
fctx.arc(start_x + (i+0.5) * cond_spacing, top_y, cond_radius, Math.PI-angle, -angle, false);
fctx.arc(start_x + (i+1) * cond_spacing, bot_y, cond_radius, -angle, Math.PI-angle, false);
fctx.fillStyle = "grey";
fctx.fill();
fctx.beginPath();
fctx.arc(start_x + (i * cond_spacing), bot_y, cond_radius, angle, Math.PI+angle);
fctx.arc(start_x + (cond_spacing * 0.5) + i * cond_spacing, top_y, cond_radius, Math.PI+angle, angle);
fctx.fillStyle = "black";
fctx.fill();
}
// Draw the wire ends:
fctx.fillRect(start_x - cond_radius, bot_y, 2.0 * cond_radius, 20);
fctx.fillStyle = "grey";
fctx.fillRect(start_x + inductor.loop_turns * cond_spacing - cond_radius, bot_y, 2.0 * cond_radius, 20);
fctx.fillStyle = "black";
// Draw left spacing arrow:
const dim_y = win_height * 0.88;
fctx.beginPath();
fctx.moveTo(start_x - 20, dim_y);
fctx.lineTo(start_x, dim_y);
fctx.lineTo(start_x - 7, dim_y + 7)
fctx.lineTo(start_x - 7, dim_y - 7)
fctx.lineTo(start_x, dim_y);
fctx.moveTo(start_x, dim_y - 7);
fctx.lineTo(start_x, dim_y + 7);
fctx.stroke();
// Draw right spacing arrow:
fctx.beginPath();
fctx.moveTo(start_x + cond_spacing + 20, dim_y);
fctx.lineTo(start_x + cond_spacing, dim_y);
fctx.lineTo(start_x + cond_spacing + 7, dim_y + 7)
fctx.lineTo(start_x + cond_spacing + 7, dim_y - 7)
fctx.lineTo(start_x + cond_spacing, dim_y);
fctx.moveTo(start_x + cond_spacing, dim_y - 7);
fctx.lineTo(start_x + cond_spacing, dim_y + 7);
fctx.stroke();
// Draw right length arrow:
fctx.beginPath();
fctx.moveTo(start_x + inductor.loop_turns * cond_spacing + 20, dim_y);
fctx.lineTo(start_x + inductor.loop_turns * cond_spacing, dim_y);
fctx.lineTo(start_x + inductor.loop_turns * cond_spacing + 7, dim_y + 7)
fctx.lineTo(start_x + inductor.loop_turns * cond_spacing + 7, dim_y - 7)
fctx.lineTo(start_x + inductor.loop_turns * cond_spacing, dim_y);
fctx.moveTo(start_x + inductor.loop_turns * cond_spacing, dim_y - 7);
fctx.lineTo(start_x + inductor.loop_turns * cond_spacing, dim_y + 7);
fctx.stroke();
// Extended lines:
fctx.strokeStyle = "grey";
fctx.beginPath();
fctx.moveTo(start_x, bot_y + 25);
fctx.lineTo(start_x, dim_y - 12);
fctx.moveTo(start_x + cond_spacing, bot_y + 10);
fctx.lineTo(start_x + cond_spacing, dim_y - 12);
fctx.moveTo(start_x + inductor.loop_turns * cond_spacing, bot_y + 25);
fctx.lineTo(start_x + inductor.loop_turns * cond_spacing, dim_y - 12);
fctx.stroke();
fctx.strokeStyle = "black";
//fctx.textAlign = "center";
fctx.font = spacing_font;
fctx.textAlign = "right";
fctx.fillText("c/a = " + inductor.spacing_ratio.toFixed(2).toString() + " ", win_width/2, win_height * 0.52);
fctx.font = turns_font;
fctx.textAlign = "left";
fctx.fillText(" N = " + inductor.loop_turns.toString(), win_width/2, win_height * 0.52);
fctx.font = "12px arial";
// Draw spacing text: (gap is to avoid collision of spacing and length texts)
fctx.textAlign = "right";
var gap = ((inductor.loop_turns * cond_spacing - cond_spacing) < 60) ? (60 - (inductor.loop_turns * cond_spacing - cond_spacing)) : 0;
const spc = inductor.spacing_ratio * cond_diameter_inches;
fctx.fillText("c = " + spc.toFixed(3).toString() + "\"", start_x + cond_spacing + 20 - gap, dim_y + 20);
fctx.fillText("(" + (spc*25.4).toFixed(3).toString() + "mm)", start_x + cond_spacing + 20 - gap, dim_y + 34);
// Draw length text:
const sol_len = inductor.loop_turns * spc;
fctx.fillText("\u2113 = " + sol_len.toFixed(3).toString() + "\"", start_x + inductor.loop_turns * cond_spacing + 20, dim_y + 20);
fctx.fillText("(" + (sol_len*25.4).toFixed(1).toString() + "mm)", start_x + inductor.loop_turns * cond_spacing + 20, dim_y + 34);
fctx.strokeStyle = "black";
if(inductor.frequency_hz <= inductor.SRF) {
fctx.fillStyle = "black";
} else {
fctx.fillStyle = "red";
}
//fctx.font = "12px courier";
fctx.textAlign = "right";
var freq = 1e-6 * inductor.frequency_hz;
fctx.font = frequency_font;
fctx.fillText("f = " + freq.toFixed(2) + " MHz", win_width-18, 18);
fctx.font = "12px arial";
fctx.fillText("\u03B4 = " + (inductor.skin_depth * 1e6).toFixed(1) + " \u03BCm", win_width-18, 32);
fctx.fillText("Rac = " + inductor.Rac.toFixed(2) + " \u03A9", win_width-18, 46);
fctx.fillText("X\u2097 = " + inductor.Xl.toFixed(1) + " \u03A9", win_width-18, 60);
var str = "Z = " + inductor.Z.re.toFixed(1);
if(inductor.Z.im >= 0.0) {
str += " + j";
} else {
str += " - j";
}
str += Math.abs(inductor.Z.im).toFixed(1) + " \u03A9";
fctx.fillText(str, win_width-18, 74);
//fctx.fillText("Z = " + inductor.Z.re.toFixed(1) + " " + inductor.Z.im.toFixed(1) + "j \u03A9", win_width-18, 74);
fctx.fillText("|Z| = " + inductor.Z.toPolar().r.toFixed(1) + " \u03A9", win_width-18, 88);
fctx.fillText("Q = " + inductor.Q.toFixed(1), win_width-18, 102);
}
recalculate();
drawDesign();
</script>
</body>
</html>