Hi all!
I'll apologise now for the brevity, I'm on my phone but I have a few burning questions that have been bothering me for a few days. (If anyone wants to see any datasheet, photos, or schematics it'll have to wait until I'm home!)
So, I'd like to make a plasma speaker. The principal is pretty simple, as I'm sure you all know. Generate HV with frequency somewhere above 20Khz, and then modulate this with audio.
Currently, I have make the plasma and all is well (using a 555 timer, IR2110 driver, and IGBT and a transformer).
The arcs are not large, maybe only half a cm at best. But this is not my concern at the moment, it's driven from a 12v supply so they're going to be small.
What I've started to realise is that I don't understand my transformer (that I made) very well, and I was hoping someone can clear a few things up for me.
I first set out to make a "flyback transformer", I have one of those DIY inductors laying around (made by a company called ferrox cube, you basically chose a ferrite with a certain al value and wind accordingly). But, it seems to me that there's no such thing as a "flyback transformer" unless it contains the blocking diode. It's more how the transformer is driven that makes it a flyback? IE, the sudden discontinuous current?
I wound thin gauge wire around the plastic bobbin to the top, then, I taped around, put the wire at the bottom of the bobbin, and started going to the top again. My reason for this (please correct me if I'm wrong!) Is that I want the electric field lines all in the same direction so that they don't cancel out, which is what I assume would happen if I went from bottom to top to bottom ect.? Then I wound a few turns of larger gauge around the inner (small gauge) coil.
Can I ask what type of transformer I have made and whether it can be considered a flyback, or is it a coupled inductor (which would be used for a flyback converter?!?)?
I really don't care what transformer I make, but I'd like to drive this differently (currently, the IGBT is the lowside switch which excited the primary coil, however this is heating the IGBT up a lot) using a half or full bridge topology, and since the ir2110 is a low and high side driver, I might as well. I'd also like to do some calculations to determine the amount of current through the primary and make sure the IGBTs won't fail, but that should be trivial. I just want to understand the transformer first!
Can anyone help shed some light on this?
Many thanks!
Max