Programming instructions

Magnetic Core
 National Instruments Corporation 2-39 Multisim Component Reference Guide
2.21 Magnetic Core
This component is a conceptual model that you can use as a building block to create a wide
variety of inductive and magnetic circuit models. Typically, you would use the magnetic core
together with the coreless coil to build up systems that mock the behavior of linear and
nonlinear magnetic components. It takes as input a voltage which it treats as a magnetomotive
force (mmf) value.
Characteristic Equation
Magnetic field intensity, H, is:
H = mmf / l
where:
mmf = magnetomotive force, the input voltage
l = core length
Flux density, B, is derived from a piecewise linear transfer function described to the model by
the (magnetic field, flux density) pairs that you input in the Circuit/Component Properties
dialog box. The final current, I, allowed to flow through the core is used to obtain a value for
the voltage reflected back across the terminals. It is calculated as:
I = BA
where:
A = cross-sectional area
ComponentRef.book Page 39 Thursday, December 7, 2006 10:12 AM