First, Chris, kind of funny. I mentioned I had actually seen that slow rise of the voltage and brushed it off as a bad scope or probe. But also, when I first built this particular build I had also noticed the limited frequency range in which the bulb would light. I built the second setup with ferrite thinking that would help but it didn't. So I concluded that the coupling between the coils was just horrible, and I put them on the shelf. 😄 My my, I step over a lot of things that are right in my face.
So, I went ahead and replicated the effect shown in Chris's video here..
I noticed in the comments of that video that someone had mentioned it might be the bulb heating up. Which kind of makes sense, I guess. But if I am of the correct understanding, voltage should be there, over the bulb, immediately, despite the resistance of the load. Current of course should rise a little as the bulb heats up and the resistance drops. But not the voltage.
So, I made a video. Two parts. The first part I have a normal MOT with the coils and I show it's not the bulb. I address the flashing at lower frequencies, and the low (upper) frequency at which the bulb goes out. I also talk a bit about how this effect cannot be due to impedance, or core material, standard explainations, etc. Then in the second part of the video I show my build of this particular configuration, on which I threw a 100 turn input coil of 0.6 mm wire, and it shows the effect. Sorry it is not as pronounced as Chris's, but it's there no doubt.
Here is my video, it got kind of long, 15 minutes, but it's good I think.
Also, at the end of the video, I mention that the effect reminds me of Chris saying (somewhere?) that the POCs act like a capacitor, and two videos come to mind. One by Steven Marks and one by Akula.
In the Steven Marks video he turns the device upside down, and it starts "winding down". I think there are other videos of his where he talks about this effect. Winding up and/or winding down, even though in this video when he turns it back upright the voltage is immediately back up. Here at about the 2:40 mark
In Akula's video, he has a similar device which he hooks up to an incandescent light bulb and shows how it takes a while for the voltage to build. His takes a bit over one minute. Here at roughly 6 minutes into the video, he shows and uses the words "as the system accelerates".
Anyway, I'm not sure if that is what we are seeing here, but it really resembles it. It definitely seems like there is more of a separation between POC interactions and the input. I'll definitely be playing with this, while trying not to step over anymore obvious effect 😀
Thanks!
Marcel