Select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer – comparison of measured and predicted

Select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer – nanoVNA described a method of using a nanoVNA to select by trial possible core and turns combinations for a transformer. This article compares the results for the FT240-43 example at 3.5MHz with calculation using tools on this … Continue reading Select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer – comparison of measured and predicted

Select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer – nanoVNA – loss components graph

Select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer – nanoVNA gave an explanation of how to use a nanoVNA or the like to select a suitable core and sufficient turns for a low InsertionVSWR broad band 50Ω transformer. Last update: 1st March, 2021, 9:09 AM

Select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer – nanoVNA

This article demonstrates the use of a nanoVNA to select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer. Simple low frequency equivalent circuit Above is a very simple approximation of an ideal 1:1 transformer where the effects of flux leakage and conductor loss are ignored. A 1:n … Continue reading Select a ferrite core material and sufficient primary turns for a low InsertionVSWR 50Ω broadband RF transformer – nanoVNA

Mornhinweg ferrite core measurements – #61

Further to Amidon’s method of rating ferrite inductors and transformers, this article discusses some interesting measurements of ferrite toroids by Manfred Mornhinweg (Mornhinweg 2019). Mornhinweg ferrite core measurements – #31 discussed his measurements of a #31 suppression sleeve. Above are his measurements of a FB-61-6873 sleeve. Essentially there are two measurements at each frequency, and … Continue reading Mornhinweg ferrite core measurements – #61

Black body emissivity of ferrite core material

Some of my articles have contained thermal pictures of ferrite cored inductors and transformers. I have been asked several times recently about the assumed emissivity and the accuracy questioned, I assume this has been discussed online somewhere. When first measuring ferrites with non-contact thermometers, I performed some experiments to discover whether the default emissivity ε=0.95 … Continue reading Black body emissivity of ferrite core material

Calculate ferrite cored inductor – rectangular cross section – enhancement – chamfered corners

The calculator Calculate ferrite cored inductor – rectangular cross section has until now assumed that the toroid has sharp corners. The corner treatment varies across commercial products, some are burnished which removes very little material, some have a chamfer or bevel, some are radiused. All of these treatments give rise to a very small error … Continue reading Calculate ferrite cored inductor – rectangular cross section – enhancement – chamfered corners

Mornhinweg ferrite core measurements – #31

Further to Amidon’s method of rating ferrite inductors and transformers, this article discusses some interesting measurements of ferrite toroids by Manfred Mornhinweg (Mornhinweg 2019). Above are his measurements of a FB-31-6873 sleeve. Essentially there are two measurements at each frequency, and the expected flux density B is in the ratio of approximately 2:1. He has … Continue reading Mornhinweg ferrite core measurements – #31

Amidon’s method of rating ferrite inductors and transformers

I have set out an initial design method for RF inductors and transformers using toroidal ferrite cores and over time I get correspondence drawing my attention to Amidon’s advice, specifically sections 1-35 and 1-36. Section 1-36 states explicitly that it is applicable to Iron Powder and Ferrite, which is interesting because they are very different … Continue reading Amidon’s method of rating ferrite inductors and transformers