figures/asy/ElectroMag.asy: Add the E&M library from my course project

For drawing a Peltier.

diff --git a/src/figures/asy/ElectroMag-test.asy b/src/figures/asy/ElectroMag-test.asy
new file mode 100644 (file)
index 0000000..ec4820b
--- /dev/null
+++ b/src/figures/asy/ElectroMag-test.asy
@@ -0,0 +1,62 @@
+/* Test suite for ElectroMag.asy.
+ *
+ * Copyright (C) 2008-2009 W. Trevor King <wking@drexel.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+import ElectroMag;
+
+real u = 1cm;
+
+Charge a = pCharge(center=(0.5u,2u));
+Charge b = aCharge(center=(0,-0.5u), q=1);
+Charge c = nCharge(center=(-3u,-0.5u), q=-3);
+Charge cs[] = {a,b,c};
+string subscripts[] = {"a"};
+Distance dab = Distance(b.center(), a.center(), scale=u, L="$r_1$");
+Distance dbc = Distance(c.center(), b.center(), scale=u, L="$r_2$");
+Distance ds[] = {dab};
+Angle abc = Angle(
+    a.center(), b.center(), c.center(), radius=.5u, L="$\theta_T$");
+Angle bac = Angle(
+    b.center(), a.center(), c.center(), radius=-0.4u, L="$\phi_x$");
+Angle as[] = {abc, bac};
+
+//write(a.center.x);
+//write(a.center.y);
+for (int i=0; i<cs.length; i+=1)
+  cs[i].draw();
+for (int i=0; i<ds.length; i+=1)
+  ds[i].draw();
+for (int i=0; i<as.length; i+=1)
+  as[i].draw();
+
+CoulombEFields((-0.5u, 1.2u), c=cs, subscripts=subscripts, scale=2u, unit=u/2);
+//Vector Fba = CoulombForce(b,a, scale=2u, unit=u);
+//Fba.draw();
+CoulombForces(c=cs, subscripts=subscripts, scale=2u, unit=u);
+
+Charge a = aCharge(center=(-2u, 2u), q=0);
+a.draw();
+Vector v = EField(a.center(), mag=u/2, dir=0,L="E"); v.draw();
+Vector v = BField(a.center(), mag=u/2, dir=90,L="B"); v.draw();
+Vector v = Velocity(a.center(), mag=u/2, dir=180,L="$v$"); v.draw();
+
+Vector Ic = Current(center=(-0.7u, 2.2u), phi=90, L="$I$"); Ic.draw();
+draw(shift(Ic.center)*scale(16pt)*unitcircle, BFieldPen, ArcArrow);
+
+a = aCharge(center=(-3u, 2u), q=-1);
+a.draw();

diff --git a/src/figures/asy/ElectroMag.asy b/src/figures/asy/ElectroMag.asy
new file mode 100644 (file)
index 0000000..52d6dd1
--- /dev/null
+++ b/src/figures/asy/ElectroMag.asy
@@ -0,0 +1,188 @@
+/* Useful functions for drawing Physics 102 figures.
+ *
+ * Copyright (C) 2008-2009 W. Trevor King <wking@drexel.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+import geometry;
+import Mechanics;
+
+
+// ---------------------- Charges -------------------------
+
+pen pChargePen = red;
+pen nChargePen = blue;
+pen neutralChargePen = grey;
+
+// charged particle
+struct Charge {
+  LabeledCircle lc;
+  real q;
+  
+  void operator init(pair center=(0,0), real q=1, real radius=2mm,
+                     pen outline=currentpen, pen fill=pChargePen, Label L="") {
+    this.lc.operator init(center=center, radius=radius, outline=outline,
+                          fill=fill, L=L);
+    this.q = q;
+  }
+
+  pair center() { return this.lc.center; }
+  void set_center(pair center) { this.lc.center = center; }
+  void draw(picture pic=currentpicture) = this.lc.draw;
+}
+
+// positive charge
+Charge pCharge(pair center=(0,0), real q=1, real radius=2mm,
+               pen outline=currentpen, Label L="")
+{
+  return Charge(center=center, q=q, radius=radius, outline=outline,
+                fill=pChargePen, L=L);
+}
+
+// negative charge
+Charge nCharge(pair center=(0,0), real q=-1, real radius=2mm,
+               pen outline=currentpen, Label L="")
+{
+  return Charge(center=center, q=q, radius=radius, outline=outline,
+                fill=nChargePen, L=L);
+}
+
+// neutral charge
+Charge neutralCharge(pair center=(0,0), real radius=2mm,
+                     pen outline=currentpen, Label L="")
+{
+  return Charge(center=center, q=0, radius=radius, outline=outline,
+                fill=neutralChargePen, L=L);
+}
+
+// auto-signed charge
+Charge aCharge(pair center=(0,0), real q=1, real radius=2mm,
+               pen outline=currentpen, Label L="")
+{
+  Charge c;
+  if (q > 0) {
+    c = pCharge(center, q, radius, outline, L);
+  } else if (q < 0) {
+    c = nCharge(center, q, radius, outline, L);
+  } else {
+    c = neutralCharge(center, radius, outline, L);
+  }
+  return c;
+}
+
+// ---------------------- Vectors -------------------------
+
+pen EFieldPen = rgb(1,0.5,0.2);    // orange
+pen BFieldPen = rgb(0.1,1,0.2);    // green
+pen CurrentPen = rgb(0.8,0.1,0.8); // purple
+
+// electric field
+Vector EField(pair center=(0,0), real mag=5mm, real dir=0, real phi=0, Label L="")
+{
+  Vector v = Vector(center=center, mag=mag, dir=dir, phi=phi, L=L, outline=EFieldPen);
+  return v;
+}
+
+// magnetic field
+Vector BField(pair center=(0,0), real mag=5mm, real dir=0, real phi=0, Label L="")
+{
+  Vector v = Vector(center=center, mag=mag, dir=dir, phi=phi, L=L, outline=BFieldPen);
+  return v;
+}
+
+Vector Current(pair center=(0,0), real mag=5mm, real dir=0, real phi=0, Label L="")
+{
+  Vector v = Vector(center=center, mag=mag, dir=dir, phi=phi, L=L, outline=CurrentPen);
+  return v;
+}
+
+// ------------------ Electric fields --------------------
+
+// Electric field at a due to b
+Vector CoulombEField(pair a, Charge b, Label L="", real scale=1mm,
+                     real unit=1mm)
+{
+  pair r = a - b.center();
+  real mag, dir;
+  mag = (abs(b.q)*(scale/length(r))^2)*unit;
+  dir = degrees(r);
+  if (b.q < 0) {
+    dir += 180;
+  }
+  Vector v = EField(center=a, mag=mag, dir=dir, L=L);
+  return v;
+}
+
+void CoulombEFields(pair a, Charge c[], string subscripts[]={}, real scale=1mm,
+                    real unit=1mm)
+{
+  Vector E;
+  string s, sub;
+  for (int i=0; i<c.length; i+=1) {
+    if (i < subscripts.length) {
+      sub = subscripts[i];
+    } else {
+      sub = format("%d", i+1);
+    }
+    s = "$E_{" + sub + "}$";
+    E = CoulombEField(
+        a, c[i], L=Label(s, position=EndPoint, align=LeftSide),
+        scale=scale, unit=unit);
+    E.draw();
+  }
+}
+
+// ---------------------- Forces -------------------------
+
+// Force of a on b
+Vector CoulombForce(Charge a, Charge b, Label L="", real scale=1mm, real unit=1mm)
+{
+  pair r = b.center() - a.center();
+  real mag, dir;
+  mag = ((a.q*b.q)*(scale/length(r))^2)*unit;
+  dir = degrees(r);
+  Vector v = Force(center=b.center(), mag=mag, dir=dir, L=L);
+  return v;
+}
+
+void CoulombForces(Charge c[], string subscripts[]={}, real scale=1mm,
+                   real unit=1mm)
+{
+  Vector F;
+  string s, subi, subj;
+  for (int i=0; i<c.length; i+=1) {
+    if (i < subscripts.length) {
+      subi = subscripts[i];
+    } else {
+      subi = format("%d", i+1);
+    }
+    for(int j=0; j<c.length; j+=1) {
+      if (i==j) continue;
+      if (j < subscripts.length) {
+        subj = subscripts[j];
+      } else {
+        subj = format("%d", j+1);
+      }
+      s = "$F_{" + subi + "," + subj + "}$";
+      F = CoulombForce(
+          c[i], c[j], L=Label(s, position=EndPoint, align=LeftSide),
+          scale=scale, unit=unit);
+      F.draw();
+    }
+  }
+}
+
+