What Is a Loading Coil?

Coils are generally referred to as looped wires. The most common coil applications are: motors, inductors, transformers, and loop antennas.

Number of coil turns

Calculation formula of coil turns

Calculation formula: N = 0.4 (l / d) power. N is the number of turns, L is the absolute unit, and luH = 10 cubic meters. d- coil average diameter (Cm).

For example, winding an inductor coil with L = 0.04uH, taking the average diameter d = 0.8cm, then the number of turns is N = 3 turns. When calculating the value, the number of turns N is slightly larger. In this way, the inductance can be adjusted within a certain range.

Production method: adopt side-by-side dense winding, select enameled wire with diameter of 0.5-1.5mm, take the coil diameter according to the actual requirements, and finally get born.

: The number of turns of the coil is first loaded and its inductance is calculated as follows: coil formula

Impedance (ohm) = 2 * 3.14159 * F (working frequency) * inductance (mH), the setting needs 360ohm impedance,

therefore:

Inductance (mH) = Impedance (ohm) ÷ (2 * 3.14159) ÷ F (working frequency) = 360 ÷ (2 * 3.14159) ÷ 7.06 = 8.116mH

From this, the number of windings can be calculated:

Number of turns = [Inductance * ((18 * turn diameter ()) + (40 * turn length ()))] ÷ turn diameter

Number of turns = [8.116 * ((18 * 2.047) + (40 * 3.74))] ÷ 2.047 = 19 turns

Calculation formula for the number of coil turns hollow inductor

Hollow inductance calculation formula: L (mH) = (0.08DDNN) / (3D + 9W + 10H)

D ------ coil diameter

N ------ Number of coil turns

d ----- Wire diameter

H ---- coil height

W ---- coil width

The units are millimeters and mH.

Coil turns calculation formula

l = (0.01 * D * N * N) / (L / D + 0.44)

Coil inductance l unit: microhenry

Coil diameter D unit: cm

Coil turns N unit: turns

Coil length L unit: cm

Frequency inductance and capacitance calculation formula:

l = 25330.3 / [(f0 * f0) * c]

Working frequency: f0 Unit: MHZ This question f0 = 125KHZ = 0.125

Resonant capacitance: c Unit: PF The meaning of this question c = 500..1000pf can be determined by yourself or determined by Q

Resonance inductance: l unit: microhenry

Calculation formula of coil turns

1. For the circular core, the following formula is available: (IRON)

L = N2AL L = Inductance (H)

H-DC = 0.4NI / l N = number of coil turns (turns)

AL = inductance

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

l = magnetic circuit length (cm)

l and AL value, refer to Microl comparison table. For example: Take T50-52 material, the coil is 5 and a half turns, the L value is T50-52 (indicating that the OD is 0.5 inches), and the AL value is about 33nH

2.Empirical formula

L = (k * 0 * s * N2 * S) / l

among them

0 is the vacuum permeability = 4 * 10 (-7). (Negative power of 10)

s is the relative permeability of the magnetic core inside the coil, s = 1 for hollow coils

N2 is the square of the number of coil turns

S coil cross-sectional area in square meters

l The length of the coil in meters

The k-factor depends on the ratio of the radius (R) to the length (l) of the coil.

The unit of the calculated inductance is Henry.

k value table

2R / lk

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 0.69

1.5 0.6

2.0 0.52

3.0 0.43

4.0 0.37

5.0 0.32

10 0.2

20 0.12

The second batch of a simple inductance calculation program, just enter the wire diameter `coil diameter` turns

Magnetic field strength = permeability X unit length coil turns X current