ETS-Lindgren 6404 Helmholtz Coil - Manual (Page 15)

Theory of Operation | 15
In SI units, the relationship is given by
R
NI
H B μ μμ 7
0
10 99 . 8 − × ≈ =
• B is the magnetic flux density in teslas
• µ is the relative permeability
• µ ο is the permeability constant
• N is the number of turns per coil
• I is the coil current in amperes
• R is the coil radius in meters
For the unloaded coil, the relative permeability, µ, is one, so that
H B =
in CGS
units, and
H B
0
μ =
in SI units.
Refer to Appendix B: Conversion Table for Magnetic Units for more unit
conversions.