1 files changed, 25 insertions, 0 deletions
diff --git a/3871/CH10/EX10.21/Ex10_21.sce b/3871/CH10/EX10.21/Ex10_21.sce
new file mode 100644
index 000000000..e22cf06d5
--- /dev/null
+++ b/3871/CH10/EX10.21/Ex10_21.sce
@@ -0,0 +1,25 @@
+//===========================================================================
+//chapter 10 example 21
+clc;clear all;
+
+//variable declaration
+V1	= 450;		//voltage in V
+V2	 = 280;		//voltage in V
+t	= 15.2;		//time in minutes
+t1	= 10.8;		//time in minutes
+C	= 2.5*10^-6;	//capacitance in F
+
+//calculations
+t12	= t*60;		//time in seconds
+t22	= t1*60;		//time in seconds
+//V2	= V1*e^(t/C*R)
+x    = V1/V2;
+y    = log(x);
+R	= t12/(C*y);
+R1  =t22/(C*y);
+//R1	= t1/(C*log(V1/V2));
+//1/R` 	= (1/R1)-(1/R)
+R11	= (R1*R)/(R-R1);		//unknown resistance in Ω
+
+//result
+mprintf("unknown resistance= %3.2d M Ω",(R11*10^-6));