Plasma Ball / globe transformer ?

[lordvader88]

I have a cheap Plasma globe that works but not ideally compared to others I've seen and I've mapped out its layout and I'm trying to learn how it really works and hope to modify it (even more than). It uses a 14pinDIP Hex inverter chip and I believe just a 10pF cap to cause oscillations. Still learning why the 14pin Hex inverter is connected the why it is.

But never mind that for now, its transformer has 5 pins total. 2 are on the same Vsupply trace, then internally connect to 2 others, which are both on the same trace, that only goes to the collector of a TIP122 NPN darlington BJT. So those 4 pins are always physically connected.

The only other pin is connected directly to the ground trace, as is the emitter of the TIP122.

So what kind of transformer is that

[Buriedcode]

Likely to be a flyback or a blocking oscillator such as this: http://www.personal.psu.edu/sdb229/plasma%20schematic.gif

See wiki: https://en.wikipedia.org/wiki/Blocking_oscillator

They can be very simple - transformer with feedback winding, transistor for a switch and maybe a couple of resistors.

I believe the transformers have a saturatable core that forms the feedback to make the primary side oscillate. 

[lordvader88]

I can through up a picture later, but how can the transformer be a "big" cube with 5 terminals, but only 2 real connections  ?

[james_s]

I'm betting two of the pins you think are internally connected are actually going to a primary winding. A high frequency transformer needs only a few turns on a low voltage winding, it will look like a short circuit to a multimeter.

Post a picture if you can though.

[t8ja]

Since the OP didn't post, here it is, without the major components though 

https://assets.nexperia.com/documents/data-sheet/HEF4069UB.pdf

[klkhbzxucv]

Hey I have the same/similar plasma ball, it seems like it could be alot more impressive than it is. Has anyone had any success in "amping" it up?

[chris_leyson]

I think the larger globes use a small TV line output transformer, or what was perhaps intended to be a very small line ouput transformer. Big clive has a nice teardown of a small 3in globe.
Hmm... not sure about "amping it up" but I wonder how well the globe would work as an antenna if you drive it with enough high voltage RF, on the 13MHz ISM band of course. What would the far field radiation pattern look like, just wondered, as one does.

[Kilrah]

Poor quality globes tend to go bad with time because of diffusion through the glass, the gas atmosphere just depletes, nothing you can really do electrically.