Bobbin Wound Transformers 510-0053 004Railroad lighting power transformer with custom terminal board.Power transformer image shows leads coming off the windings.Side view of power transformer showing (blue) ring tongue connecting wiring to custom board.Image shows the primary windings (left) and the secondary windings (right).

Bobbin Wound Transformers – Custom Built


Butler Winding designs and manufactures Bobbin Wound Transformers for a variety of power supply and power conversion applications. Bobbin wound transformers may be designed in a wide variety of shapes and sizes.

btn_bobbin_wound_theoryA Bobbin Wound Transformer is a transformer that is designed with the coil wound on a coil form or bobbin. The core structure is then mounted to the bobbin. Bobbin wound transformers can be designed to operate from 60Hz, or line frequency, well into the MHz range.

Where are Bobbin Wound Transformers found?

  • Switch mode power supplies
  • Power conversion applications
  • Circuit isolation applications
  • Filter circuits
  • Any application that the transformer can be designed on a bobbin or coil form
  • Design upper limits of a Power Transformer:

Typical minimum requirements to be specified for a Bobbin Wound Transformer are:

  • Power rating in VA.
  • Operating frequency in Hz.
  • Number of primary windings.
  • Number of secondary windings.
  • Operating voltages levels.
  • Operating current levels
  • Operating frequency is needed for core calculations and wire sizing.
  • Core material is selected for the known operating frequency or frequencies which can be anything from silicon steel laminations to a ferrite core structure.
  • Other bobbin wound transformer design considerations are space limitations and mounting technique.
  • Lead terminations, if needed, may also be specified through the design of a Bobbin Wound Transformer.

Bobbin wound transformer designs vary widely in terms of power rating, voltage and current levels (turns ratios), operating frequency, size, impedance, bandwidth (frequency response), packaging, winding capacitance, and other parameters.

PHOTOS Bobbin Wound Custom Projects
PHOTOS Bobbin Winding Process