6 files changed, 33 insertions, 0 deletions
diff --git a/3630/CH20/EX20.1/Ex20_1.sce b/3630/CH20/EX20.1/Ex20_1.sce
new file mode 100644
index 000000000..762d75d37
--- /dev/null
+++ b/3630/CH20/EX20.1/Ex20_1.sce
@@ -0,0 +1,7 @@
+clc;
+t=0.018;
+I=50;
+D=(I^2)*t;
+if (D <= 145) then
+    disp('device can handle this surge');
+end
diff --git a/3630/CH20/EX20.2/Ex20_2.sce b/3630/CH20/EX20.2/Ex20_2.sce
new file mode 100644
index 000000000..fcf54f191
--- /dev/null
+++ b/3630/CH20/EX20.2/Ex20_2.sce
@@ -0,0 +1,6 @@
+
+clc;
+D=60;  //I^2*t(rated) value
+Is=100;
+tmax=(D)/(Is)^2;
+disp('ms',tmax*1000,"tmax=");//The answers vary due to round off error
diff --git a/3630/CH20/EX20.3/Ex20_3.sce b/3630/CH20/EX20.3/Ex20_3.sce
new file mode 100644
index 000000000..d67e2fcdc
--- /dev/null
+++ b/3630/CH20/EX20.3/Ex20_3.sce
@@ -0,0 +1,5 @@
+clc;
+D=60; //I^2*t(rated) value
+ts=0.020;
+Ismax=(D/ts)^0.5;
+disp('A',Ismax,"Ismax=");//The answers vary due to round off error
diff --git a/3630/CH20/EX20.4/Ex21_4.sce b/3630/CH20/EX20.4/Ex21_4.sce
new file mode 100644
index 000000000..7d5ae945e
--- /dev/null
+++ b/3630/CH20/EX20.4/Ex21_4.sce
@@ -0,0 +1,5 @@
+clc;
+R2=2400;
+R1=240;
+Vdc=(1.25)*((R2/R1)+1);
+disp('V',Vdc,"Vdc=");//The answers vary due to round off error
diff --git a/3630/CH20/EX20.5/Ex20_5.sce b/3630/CH20/EX20.5/Ex20_5.sce
new file mode 100644
index 000000000..0459765b6
--- /dev/null
+++ b/3630/CH20/EX20.5/Ex20_5.sce
@@ -0,0 +1,5 @@
+clc;
+n=0.8;
+Vbb=18;
+Vp=(n*Vbb+0.7);
+disp('V',Vp,"Vp=");//The answers vary due to round off error
diff --git a/3630/CH20/EX20.6/Ex20_6.sce b/3630/CH20/EX20.6/Ex20_6.sce
new file mode 100644
index 000000000..7d24bbe33
--- /dev/null
+++ b/3630/CH20/EX20.6/Ex20_6.sce
@@ -0,0 +1,5 @@
+clc;
+c=3*10^(17);
+f=150*10^(12);
+lemda=c/f;
+disp('nm',lemda,"lemda=");