First idea to measure high inductance transformers and choke coils with a Maxwell bridge

A first setup (experimental) of a circuit (maxwell bridge) with which you can measure the inductance of “heavy” coils.

That means: coils in the Milli Henry range or even the Henry range, say with laminated iron/steel cores or substantial ferrite cores, like on 200 KHz or so.

So the video is not about measuring coils in the 800 Micro Henry to 5 Micro Henry range, these coils are used in Medium wave or Long wave applications/radios etc. (200 KHz-2 MHz). Or go up to Shortwave (2 MHz – 30 MHz) frequencies.

They can be tested better with a test oscillator (2 MHz-10 MHz), many circuits about how to do that are on my YT Channel.

So here it is all about a first idea to test “heavy” coils, say choke coils for 50/60 Hertz or (say: old school) transformers with copper wire windings made for 110 V/230 V at 50/60 Hertz. Perhaps even ferrite coils used in the (say) 100-200 KHz band in case of modern switched power supplies.

I will try to elaborate the circuit much better to make it in such a way that direct measurements of “heavier coils” can be read out with this Maxwell Bridge.

Perhaps viewers are more handy with these formulas & calculations, because 1 Henry is such a big value, just like 1 Farad. So I am often struggling with negative values, like -6 etc. But scientists know how to handle that and can (perhaps) take profit of this first setup.



Of course there are good quality inductance meters for professional use, but anyway, it is always interesting to do experiments.

Video NOT made for children.

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Be aware of that, I saw on the internet my circuits reproduced in a poor or not proper way.

I also found that people probably republish my circuits under phantasy names and/or with phantasy properties. Sometimes they want to find gold with them. I take distance from all these fake claims; I cannot help that it happens, sorry. Upload 6 January 2020.