Help needed with toroid ferrite and bobbin

Thread Starter


Joined May 2, 2010
Hi, I am building a dc-dc buck converter and one of the parts is a 1:1 transformer using a toroid ferrite but I am having trouble finding a toroid bobbin to mount it on.

The book I am taking the schematic from says the ferrite should be mounted to a 4 pin gull wing surface mount header but goggling it doesn't bring back anything along with the toroid bobbin.

I have found a Kemet 10mm x 10mm toroid ferrite and looking on the manufacturing website I couldnt find a bobbin to go with it.

Does anyone know where I can find a bobbin, 4 pin gull wing surface mount header or something else?


Joined Sep 21, 2007
I am somewhat confused. A toroid is wound either directly on the toroid or, if you need some insulation or separation then you need to wind some tape first. I cannot see how you can use a bobbin on a toroid because toroid cores are a single piece and do not come apart. Maybe I am missing something. Look at toroids in switching power supplies and you will see what I mean.

Edit: have a look at
and it will become clear that it is just not possible to wind the coil on a bobbin and then insert the core.
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