As discussed in previous article, all the constraints for ferrite core inductor design is accumulated in single constant. For power electronic based converter circuits, filter inductor core design, according to requirement of converter is important. Geometric constant $K_g$ takes into account all these constraints and give benchmark for minimum core size, shape, window area and other geometric attributes and geometric constant table gives standard values.

## Geometric Constant Table for Ferrite Core Inductor

$K_g$ (Geometric constant) is given by

$$ K_g \geq \frac{\rho L^2 I^2_{m} }{B^2_{m}R K_u} \times 10^8 (cm^5) $$

According to all the design requirements of ferrite core based inductor design, right hand side will give a constant value in $cm^5$. This constant will provide minimum threshold for standard tables to lookup for geometric values for ferrite core.

Therefore geometric constant $K_g$, considers all the constraints and gives minimum values for physical parameters of core.

So, for different type of ferrite cores, physical parameters of core is defined. Some of the geometric constant tables are given below:

## EE Type Ferrite Cores

## POT Type Ferrite Cores:

## PD and PQ type Ferrite Core

In ** Kg** method, all the constraints are lumped in single constant and design parameters are chosen according to these tables. These standard tables are referred to following articles for ferrite core based inductor design when geometric constant (Kg) method of inductor design is used.

Finally, more articles, or projects from experienced engineer, stay tuned. Or contact us or share your experiences through us.