If this is for simulation, please see this Project:

https://easyeda.com/andyfierman/Welcome_to_EasyEDA-31e1288f882e49e582699b8eb7fe9b1f

in particular, Section (3).

Then see:

https://easyeda.com/example/Transformers_and_coupled_inductors-LWewOI0ic

If it not for simulation, please read the same Project:

https://easyeda.com/andyfierman/Welcome_to_EasyEDA-31e1288f882e49e582699b8eb7fe9b1f

but skip section (3).

If it for advice on how to physically make such a transformer then first you need to specify the transformer and after that Google is your friend.

No, this is for simulation only. The transformer that I what needs to have 3 coils under a ferrite core. One coils with 9 turns, another with 35 and the last with 1700 turns. All coils are separated with means 6 connections points.

No, this is for simulation only. The transformer that I want needs to have 3 coils under a ferrite core. One coils with 9 turns, another with 35 and the last with 1700 turns. All coils are separated with means 6 connections points

• Just specifying a transformer as 3 turns, 35 turns and 1700 turns on a ferrite core is not enough.

To simulate a transformer or coupled inductor you need to know either:

1. at least the current in the primary winding, the number of turns for each winding, the magnetic properties such as permeability, cross sectional area and effective magnetic path length of the core material;

or,

2. the inductance of each winding and the coupling between them (assuming that they are all coupled equally to each other).

In fact if you do (1), this will allow you to calculate the two parameters you need to (2).

• The information that you need to model your transformer in spice depends on what you want to use it for in your simulation.

• In spice you can specify transformer in a number of ways.

a) The simplest is ideal transformer which only requires a turns ratio.

Such a model works down to DC and exhibits none of the expected magnetic transformer behaviours such as a basic high pass response and core saturation.

This transformer would be of little or no use for example if you are trying to make a self-oscillating high voltage generator thaqt relies on the transformer magnetic properties to work (such as in a blocking oscillator).

b) A slightly better model is an ideal transformer with a finite primary inductance. This only adds the basic highpass response because it does not work at DC.

c) A better model adds some core effects to this single primary inductance.

d) The next step up is to model the transformer as individual windings each of which can optionally have a number of more realistic behaviours modelled within it such as hysteresis, saturation, coupling factor and leakage inductances.

• This is generally the best type of model to use for most simulations.

Basically for any transformer simulation more complex than (a) you need to know the turns ratio and at least a primary inductance.

• So you need to do some work on specifying your transformer.