Advantages and challenges of bifilar and trifilar coil winding process

coil winding process

Producing an electromagnetic coil winding process requires wires of good conductivity wounded in a specific shape such as spiral, helical etc. The dimension and shape of a coil depend on many factors such as inductance, resistance, the intensity of the magnetic field, etc. For that reason, manufacturers strategically decide the shape of an electromagnetic coil to make it more effective. 

Bifilar and trifilar coils:

On that note, a bifilar coil is a specific type of coil that contains two winds, placed parallelly and closely separated from each other. You can develop this design with the addition of two insulated conductors. Bifilar coils serve multiple purposes such as to increase the potential difference or to divert the flow of current into opposite directions. In this time, the self-inductance of the electromagnetic coil becomes null or void. You can find extensive use of bifilar coils in UBSs, HDMI cables, Laptop charging cables. They reside within the Ethernet cables and make the reception and transmission of magnetics a flawless process. 

Similar to bifilar coil winding, a trifilar coil contains three spools with three separate winds. Joining ultra-fine wires in a bifilar or trifilar coil can be very much difficult if you follow the traditional, heat-based soldering system. It causes several problems such as oxidation, low-conductivity, reduced durability, etc. To avoid all these problems, the best to way to connect ultra-fine wires is thermo-pressure bonding technology, a state-of-the-art technology that is very much efficient in manufacturing good quality bifilar and trifilar coils without any drawback.


With rapid upgradation of technology, electronic devices are getting small in size, which necessitates the requirement of micro coils. However, in order to prepare micro coil-based equipment (especially using bifilar and trifilar coils), designers and engineers face a wide range of challenges. We have mentioned some of the vital ones below;

  • Mass-production of bifilar and trifilar coils for cost-savings.
  • Ensuring a safe and sound production procedure without any threat of hurting wind isolation.
  • Very strict and compact tolerance level.
  • Maintaining optimum quality for greater durability and longevity of the micro coils.
  • Placing different components correctly with the support structure.

In simple terms, with an increased number of coils within an equipment, the complexity level also increases to prepare that equipment at a reasonable cost. Besides, it also becomes difficult to ensure a high quality avoiding all constraints. 


If bifilar and trifilar coils are expensive and tricky to prepare, then why would you buy such coils? Well, here are some advantages of bifilar and trifilar coils from which you can understand why they are important and in-demand in the market.

  • Bifilar and trifilar coils are an obvious option if your device requires a steady flow of current both in the parallel and opposite direction.
  • A bifilar or trifilar coil is always a better choice than wire-wounded resistors.
  • These coils help your device to remove excess energy stocked up within the stray magnetic flux.


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