N.R.M.R.E. An investigation.

[icarus]

I am the author of the video mentioned by Grumage:

https://www.youtube.com/watch?v=iER4K1O7iMc

The circuit also works with a different transistor from TIP122, eg. TIP41C or other similar NPN.
I continued to experiment with this circuit: the following videos show the state of things.

https://www.youtube.com/watch?v=RgDTvqFr6bY

https://www.youtube.com/watch?v=ye1-Z7lfrmM

Now I'd like to share strategies and impressions to go further with others experimenters.
Maybe a bone every now from Nelson would not be a bad thing.... 

Who knows, sooner or later, maybe
But in any case thanks to Nelson for this circuit and for all his videos

Ciao

Icarus aka Mauro aka Ciucianebbia

[itsu]

I also did a replication last year together with Grumage.

I however never got this prolonged oscillation after disconnecting the base that Graham had with his setup.
Not even when using a wire through the toroid connected to copper tape around the HV radiant transformer (see 3th video).

My 3 video's of this replication are here:

https://www.youtube.com/watch?v=YoG8wTYa7eU&t=7s
https://www.youtube.com/watch?v=ceAHCQpnqZU
https://www.youtube.com/watch?v=JeIrnndrdnw

My redraw of the circuit can be seen below.

Regards Itsu

[Grumage]

Thanks Icarus and itsu.

A great start to the topic.

[TinselKoala]

Thanks for that redraw Itsu, you saved me the trouble. Now the resemblance to some Joule Thief circuits is easier to see.

A question about the "HV Radiant" transformer though... it appears you have labelled it as a step-down transformer, with the lower voltage winding on the HV output side. Is this correct? I can't quite wrap my mind around that.

On the original schematic it looks to me like the transformer is wired as step-UP , which makes more sense to me.

Also, does the "HV Radiant" share a common ground with the Negative rail of the power supply? Or is the Negative rail "floating" and the HV Radiant grounded to Earth?

[TinselKoala]

The 3n247 seems like an odd choice for a bridge rectifier that is supposed to be used in an "HV radiant" output circuit. Comments?

The closest fast diodes to the MUR440 that I have on hand are UF3003. Instead of 400V, 4 A these are rated 300V, 3A. If my local supplier doesn't have the MUR440 in stock for a reasonable price (1.00 USD or less, checking tomorrow) I'll have to use the UF3003s when I get around to constructing the circuit. Or I may go "overkill" and use MUR1560 which I know he does stock for about a dollar each.  Comments?

And I intend to use a small CRT yoke ferrite for the "toroid". Comments?


I'm attaching some data sheets below.