Calculate the diameter of d line.
Calculation formula of inductance: coil formula
Impedance (ohm) = 2 * 3. 14 159 * F (working frequency) * inductance (mH), and the setting needs 360 ohm impedance, so:
Inductance (mH) = impedance (ohm) ÷ (2*3. 14 159) ÷ F (working frequency) = 360 ÷ (2 * 3.14159).
Accordingly, the number of windings can be calculated:
Number of coils = [inductance * {( 18* coil diameter (inches)) +(40 * coil length (inches)}] coil diameter (inches)
Laps = [8.116 * {(18 * 2.047)+(40 * 3.74)}] ÷ 2.047 =19 laps.
The calculation formula of air-core inductance: L (MH) = (0.08 d.d.n.n)/(3D+9 w+10h).
D- coil diameter
Number of turns of n- coil
D-line diameter
H coil height
W-coil width
The units are mm and mH respectively. .
Calculation formula of inductance of air-core coil:
l=(0.0 1*D*N*N)/(L/D+0.44)
Coil inductance l unit: microhenre
Coil diameter d unit: cm
Coil turns n unit: turns
Coil length l unit: cm
Calculation formula of frequency inductance and capacitance:
l=25330.3/[(f0*f0)*c]
Operating frequency: f0 unit: MHz F0 =125khz = 0.125.
Resonant capacitance: c Unit: PF c=500... 1000pf can be determined by yourself or q.
Value decision
Resonant inductance: l unit: microhenre
Calculation formula of coil inductance
For a circular magnetic core, the following formula can be used: (iron)
L = N2。 Al l = inductance (h)
H-DC=0.4πNI/l N= number of turns of the coil (number of turns)
AL= inductance
DC= DC magnetizing force I= passing current (a)
L= length of magnetic circuit (cm)
For the vALues of l and al, please refer to the MIL comparison table. For example, the T50-52 material roll has 5 and a half turns, and its L value is T50-52 (indicating that the outer diameter is 0.5 inches), and its al value is about 33nH after looking up the table.
L=33。 (5.5)2=998.25nH≒ 1μH
When the current of 10A flows, its L value can be changed from l=3.74 (look-up table).
H-DC = 0.4 π Ni/L = 0.4× 3.14× 5.5×10/3.74 =18.47 (after looking up the table).
You can know the degree of l value decline (μi%).
empirical formula
L=(k*μ0*μs*N2*S)/l
In ...
μ0 is the permeability of vacuum =4π* 10(-7). (/kloc-negative seventh power of 0/0)
μs is the relative permeability of the iron core inside the coil, and μs= 1 when the coil is hollow.
N2 is the square of the number of coils.
Cross-sectional area of S coil, in square meters.
L the length of the coil, in meters
The k coefficient depends on the ratio of the radius (r) to the length (l) of the coil.
The unit for calculating inductance is Henry. K value table
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 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
examination
1. inductance
The inductance value of the color ring is tested by Q-meter, LCR-meter or impedance analyzer, and the signal is fixed inductance: read the inductance value directly or use Q-meter when the frequency is specified. Inductance used in high current lines: 1KHZ or 100KHZ.
2. Metamorphic energy
No-load Q value is tested by Q instrument, LCR instrument or impedance analyzer, and the test frequency is determined after the inductance value is tested or between different designated frequencies. But for the large current line inductance, the group pit is determined and the Q value can be ignored.
3. DC resistance
Test with a digital multimeter.
4. Self-resonant frequency
Use Q meter, impedance analyzer or network analyzer for testing.