, , , .. . , .
1) l/l
l/l , .
, . ((1), (3)) .. . , l/l.
2) D/l
, D , . , . D , .. U = U, ( ), , .. . D/l,l/D.
3) l/D
l/D D/l. , l , . 3 23, 3 90. 23 I23 23 90, .
.. 13 23 I23 23
, L23 13, .. 23, 13.
, , .. . 3 15¸20% . 3 13, 23 f3 = f13, 23 40¸60% 23 = 4,443×f1W23. 1. 40-60%. , . l/l .