Formula for calculating the inductance of the coil:

1. According to the circular CORE, the following formula can be used: (IRON)

The L=N2.AL L= inductance (H)

H-DC=0.4 PI NI / L N= the number of turns of the coil (ring)

AL= induction coefficient

H-DC= DC magnetizing force I= by current (A)

The l= path length (CM)

L and AL values, can refer to Microl table. For example: in T50-52 material, the coil 5 and a half circle, the L value is T50-52 (say OD is 0.5 inches), checking the table and its AL value is about 33nH

L=33. (5.5): 2=998.25nH = 1 H

When the current flowing through the 10A, the L value changes from l=3.74(look up table)

H-DC=0.4 n NI / L = 0.4 * 3.14 * 5.5 * 10 / 3.74 = 18.47 (look up table after)

To understand the L value decreased degree (i%)

2. Introduce an empirical formula

L= (k* 0* s*N2*S) /l

Among them

Mu 0 is the permeability of vacuum =4 PI *10 (-7). (10 minus seven party)

S for the relative permeability of inner coil core, hollow coil s=1

N2 is the number of square coil

The cross-sectional area of the S coil, the unit square meters

L the length of the coil, the unit for metres

The K coefficients, depending on the coil radius (R) and the ratio of the length(L).

Inductance calculated unit for Henry.

The table of K values

2R/l K

0.1 0.96

0.2 0.92

0.3 0.88

0.4 0.85

0.6 0.79

0.8 0.74

1 0.69

1.5 0.6

2 0.52

3 0.43

4 0.37

5 0.32

100.2

200.12