Negative Resistance in CFL tubes

[kcarring]

In playing around with home made CFL battery powered drivers, - and - doing measurements, I have stumbled across something that is very odd to me, though it is probably only due to my lack of understanding.

When I measure the activity of a CFL tube, it seems to exhibit negative resistance. Is this to be expected? Of course, my experiments have all been when the tube is driving, therefore it's not much of a "resister" when you lose all of your power to it... but...

[FRC]

kcarring

In playing around with home made CFL battery powered drivers

That is something else I wanted to ask you about. Check your PM.

FRC

[skaght]

Any noble gas tube/light should display negative resistance. Before the gas is electrified into a plasma, the resistance is very high for the tube. When the noble gas turns into a plasma, resistance drops rapidly as current increases dramatically. Voltage holds steady or even decreases. If you plot voltage versus current you'll get your negative resistance. It's one of the reasons I get so excited about working with CFLs, neon tubes and such...

[mikrovolt]

negative resistance in an efficient cfl circuit

looking at figure 5 in the pdf
compare the orange wave to the green wave.
notice that they alternate. this circuit takes advantage of the the v and i
characteristics (negative resistance) called royer converter

http://www.diodes.com/_files/products_appnote_pdfs/zetex/an17.pdf

some concider this data sheet as a control to compare or modify a test circuit.
thereby allowing others to benefit by using scientific method.

[kcarring]

looking at figure 5 in the pdf
compare the orange wave to the green wave.
notice that they alternate. this circuit takes advantage of the the v and i
characteristics (negative resistance) called royer converter

http://www.diodes.com/_files/products_appnote_pdfs/zetex/an17.pdf

some concider this data sheet as a control to compare or modify a test circuit.
thereby allowing others to benefit by using scientific method.

Thanks! That is awesome!

[mikrovolt]

looking at figure 5 in the pdf
compare the orange wave to the green wave.
notice that they alternate. this circuit takes advantage of the the v and i
characteristics (negative resistance) called royer converter

http://www.diodes.com/_files/products_appnote_pdfs/zetex/an17.pdf

some concider this data sheet as a control to compare or modify a test circuit.
thereby allowing others to benefit by using scientific method.

I need to say that the circuit I posted was to show negative resistance on the oscilloscope. The circuit is not DC pulse driven, it does not have back emf spikes or bifiliar coils and its temperature is not derived from cop> 16. it does however have fairly good efficiency and could be modified.