1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
/* Program to calculate the inductance of a coil
*
* Reference: E. Jahnke and F. Emde, _Tables of Functions_,
* 4th edition, Dover, 1945, pp 86-89.
*/
double sin(), cos(), atan(), ellpe(), ellpk();
double d;
double l;
double N;
/* double PI = 3.14159265358979323846; */
extern double PI;
main()
{
double a, f, tana, sina, K, E, m, L, t;
printf( "Self inductance of circular solenoidal coil\n" );
loop:
getnum( "diameter in centimeters", &d );
if( d < 0.0 )
exit(0); /* escape gracefully */
getnum( "length in centimeters", &l );
if( d < 0.0 )
exit(0);
getnum( "total number of turns", &N );
if( d < 0.0 )
exit(0);
tana = d/l; /* form factor */
a = atan( tana );
sina = sin(a); /* modulus of the elliptic functions (k) */
m = cos(a); /* subroutine argument = 1 - k^2 */
m = m * m;
K = ellpk(m);
E = ellpe(m);
tana = tana * tana; /* square of tan(a) */
f = ((K + (tana - 1.0) * E)/sina - tana)/3.0;
L = 4.e-9 * PI * N * N * d * f;
printf( "L = %.4e Henries\n", L );
goto loop;
}
/* Get value entered on keyboard
*/
getnum( str, pd )
char *str;
double *pd;
{
char s[40];
printf( "%s (%.10e) ? ", str, *pd );
gets(s);
if( s[0] != '\0' )
{
sscanf( s, "%lf", pd );
printf( "%.10e\n", *pd );
}
}
|
