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Air core 5uH inductors

A project log for DIY CISPR-25 LISN

Home made two channel 5uH LISN (Line impedance stabilization network) for conducted emission measurements up to 60V systems.

kevarekkevarek 08/19/2021 at 17:320 Comments

Inductor L1 has been designed with following online calculator: https://hamwaves.com/inductance/en/index.html#input

Aim was to achieve up to use copper wire thick enough to allow 30A RMS. Rule of thumb for the design is to keep its diameter D somewhat comparable to its length. Below is the calculator output that was used to model its plastic core for support.

Just for fun I have plotted the windings effective series resistance considering also skin effect.

 

Plastic core support to allow easy winding and good tolerances for both wound inductors.

Plastic spacer and holder that keeps the coils centered within the housing.

Assembled inductors were marked as 1DOT and 2DOTS and measured using LCR meter Kust LM1050A. Both seem to have almost identical parameters and good enough to be used for CISPR-25 5uH LISN.

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