Sci-Wcalc: air_coil

Sci-Wcalc: air_coil_calc

air_coil_calc - Single layer air core solenoid inductor analysis

SYNOPSIS

[L, Q, SRF, len_out, fill_out, lmax] = air_coil_calc(N, len, fill, AWG, rho, dia, freq, flag)

PARAMETERS

INPUT PARAMETERS

N : Number of turns
len : length of the coil (meters)
fill : ratio of coil length to closewound length
AWG : wire size (American Wire Gauge)
rho : resistivity of wire (ohm-m)
dia : inside diameter of coil (meters)
freq : analysis frequency (Hertz)
flag : used to calculate coil length.
- flag=0 : the length given by len is used.
- flag=1 : the length is calculated from the wire size, number of turns and fill input.

OUTPUT VALUES

L : calculated inductance (Henries)
Q : calculated quality factor
SRF : calculated self resonant frequency (Hertz)
len_out : length used for the analysis (meters)
fill_out : fill used for the analysis
lmax : maximum (closewound) inductance

DESCRIPTION

Function to analyze the electrical characteristics of a single layer, uniformly spaced, air core, solenoid inductor. The physical dimensions of the coil are given as inputs and the inductance, quality factor, and self resonant frequency are calculated.

EXAMPLE

 // number of turns
N=5;
 // we'll use the fill parameter instead
len=0;
 // the coil is 20% longer than the minimum
fill=1.2;
 // wire size
AWG=22;
 // resistivity of copper (ohm-m)
rho=1.72e-8;
 // 0.25 inches inside diameter
dia=0.25*0.0254;
 // 10 MHz operation
f=10e6;
 // use fill to calculate length
flag=1;
[L,Q,SRF,len_out,fill_out,Lmax] = air_coil_calc(N,len,fill,AWG,rho,dia,f,flag);
disp(sprintf('L=%g nH',L*1e9));
disp(sprintf('Q=%g at %g MHz',Q,f/1e6));
disp(sprintf('Self Resonant Freq=%g MHz',SRF/1e6));
disp(sprintf('Length=%g inches',len_out/0.0254));
disp(sprintf('Fill=%g',fill_out));
disp(sprintf('Lmax=%g nH',Lmax*1e9));