# Replicate transformer made from inductor

**URL:** <https://forum.digikey.com/t/replicate-transformer-made-from-inductor/38882>\
**Category:** Inductors, Coils, Chokes\
**Tags:** coilcraft, magnet-wire, tech-tips, associated-products\
**Created:** [February 16, 2024, 6:37pm UTC](https://forum.digikey.com/t/replicate-transformer-made-from-inductor/38882 "2024-02-16T18:37:11Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![spaisner](https://avatars.discourse-cdn.com/v4/letter/s/8491ac/32.png) [@spaisner](https://forum.digikey.com/u/spaisner)\
**Post date:** [February 16, 2024, 6:37pm UTC](https://forum.digikey.com/t/replicate-transformer-made-from-inductor/38882/1 "2024-02-16T18:37:11Z")

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![IMG_1545](https://global.discourse-cdn.com/digikey/original/3X/7/b/7b5d4fd38fd895fa0d47d7e77e4460841fb46f38.jpeg)

The item is a coilcraft component **143-11J12L** but a former engineer wrapped it with a secondary wire that I’m told changes it from a inductor to a transformer. That engineer is long gone and we don’t really know the purpose or how to replace it.

Can anyone help me understand this and replace it?

-Sara

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**Author:** ![David\_1768](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/david_1768/32/9762_2.png) [@David\_1768](https://forum.digikey.com/u/David_1768)\
**Post date:** [February 16, 2024, 6:45pm UTC](https://forum.digikey.com/t/replicate-transformer-made-from-inductor/38882/2 "2024-02-16T18:45:36Z")

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Hello spaisner, welcome to the DigiKey TechForum.  
I’m not an engineer, and I do not know why the wire was wrapped around the inductor.  
If you have some information on the design, or a copy of the schematic, maybe one of the engineers may be able to help with this.

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**Author:** ![PaulHutch](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/paulhutch/32/3357_2.png) [@PaulHutch](https://forum.digikey.com/u/PaulHutch)\
**Post date:** [February 17, 2024, 11:49am UTC](https://forum.digikey.com/t/replicate-transformer-made-from-inductor/38882/3 "2024-02-17T11:49:26Z")

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Welcome to the forum.

Yes, that is an inductor modified into a simple transformer.

> **[Inductor](https://en.wikipedia.org/wiki/Inductor)**
>
> An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when an electric current flows through it. An inductor typically consists of an insulated wire wound into a coil.
> When the current flowing through the coil changes, the time-varying magnetic field induces an electromotive force (emf) (voltage) in the conductor, described by Faraday's law of induction. According to Lenz's law, the induced voltage has a polarit...

> **[Transformer](https://en.wikipedia.org/wiki/Transformer)**
>
> In electrical engineering, a transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer's core, which induces a varying electromotive force (EMF) across any other coils wound around the same core. Electrical energy can be transferred between separate coils without a metallic (conductive) connection between the two circu...

Given the simple additional 2 turn winding I suspect the performance characteristics aren’t very critical.

So simply starting with a new Coilcraft part and duplicating the extra winding based on how it looks might work.

The wire you want to use is a special purpose type named magnet wire (first used for electromagnets).

> **[Magnet wire](https://en.wikipedia.org/wiki/Magnet_wire)**
>
> Magnet wire or enameled wire is a copper or aluminium wire coated with a very thin layer of insulation. It is used in the construction of transformers, inductors, motors, generators, 
> speakers, headphones, hard disk head actuators, electromagnets, electric guitar pickups, and other applications that require tight coils of insulated wire.
> The wire itself is most often fully annealed, electrolytically refined copper. Aluminium magnet wire is sometimes used for large transformers and motors. The ...

Here’s the DigiKey options:

> **[Magnetics - Transformer, Inductor Components | Magnet Wire | DigiKey Electronics](https://www.digikey.com/en/products/filter/magnetic-wire/934?s=N4IgTCBcDaILYEMDmA7ApgFwAQHcCWATmiALoC%20QA)**
>
> Magnet Wire are in stock at DigiKey. Order Now! Magnetics - Transformer, Inductor Components ship same day

If that doesn’t work you’ll need the schematic diagram for the circuit.

If you don’t have the schematic, then you’ll need to create one by reverse engineering the circuit. (which won’t be difficult based on component density shown in the photo)