Correction to the video: I was not searching for the “resonance frequency” of 50/60 Hertz transformers, but for the best performance of small 50 Hz/60 Hz (mains) transformers on other frequencies in the 50 Hz-1000 Hertz range. That has only “something” to do with the resonance phenomenon.
It plays a minor role (though here is a link).
In this video there are 2 questions:
Can 50 Hertz or 60 Hertz (mains) transformers be used on other frequencies?
How good is their energy “transport” in such a case? Do they give enough energy out to drive another electronic device on their HV side (here: a noble gas lamp)?
The answer is given in the video. There are 2 test methods, one simple: (battery/button switch/resistor) and one with the help of a Darlington Driver circuit, made with a BD 139 and a 2N3055, driven by a square wave generator with variable frequencies, variable output levels, a variable duty cycle.
Some transformers made for 50 Hz or 60 Hz have a better energy “transport” from the primary to the secondary winding on a somewhat higher frequency (somewhere in the 100 Hertz-800 Hertz range, that depends on the transformer properties).
It depends a lot on how the transformer was constructed: e.g. the windings ratio, volume of the (laminated steel) core and other properties.
In general: a high volume metal (laminated) steel/weak iron core is not able to change its magnetic field quickly, thus limiting the usable frequency on which it can transport its energy from the primary to the secondary (due to back EMF).
The video shows how you can test these properties. It shows experimental results + schematics that are usable in practice to find out: a) the ideal “resonance” frequency b) the maximum energy out (noble gas lamp used as a good indicator) and C) how such a transformer can act when it is driven by different frequencies and duty cycles.
Please note: the DC resistance of these coils (showed in the video) differs from the AC resistance (50 Hz, 60 Hz, other frequencies in the 50-1000 Hertz range), because the resistance of a coil is frequency dependent.
All the videos hat I have published on You Tube can be found via my Channel Trailer: Link is
In thematic order you can find these video’s under the “comments” section.
Important: to find all the links to the (+/-700) video’s on my YT Channel, select, in the comments section, “NEWEST FIRST”
My books about electronics are available via the website from “Lulu”, search for author “Ko Tilman” there.
There is an important video via which you can buy a document where I give links to many of my video’s, published between 2010 and 2018.
Link is:
My books are also available via Barnes and Noble and via Amazon.
Regarding all my video’s: I constantly keep them actual, so the original video’s with the most recent information are always on YouTube. That is the source, and search there. When my video’s are reproduced or re-edited on other websites/channels you can not (!) be sure about the original content (=really working electronics with real properties for a purpose) and important adaptations to the circuits.
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 13 November 2019.
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