Royer Oscillator Question

[Rtech]

I have a problem, in that the poly caps usually associated with this type of cct, have failed ,causing the usual fault of blowing transistirs.The caps are 0.27uF(270nF),250v,standard 5% Tolerance.
As you can see I am in the UK and for some reason this does not seem to be a preferred value, as 0.15, 0.22,0.33uF are all freely available from RS and Farnell BUT not the correct value.What would be the effect of fitting the 0.22 or the 0.33 in lieu ???.

[Toasty]

Re: Royer Oscillator Question

Assuming you mean the cap across the primary of the transformer, it will cause a change in oscillator frequency. 2 - 0.15's in parallel should get you close enough. That tolerance is very tight, so perhaps not, though. 0.27 is a standard number, so it shouldn't be that hard to locate.

[Rtech]

Re: Royer Oscillator Question

I reckoned it would change the freq,but am still not certain,what effect that would actually have on the B/Ls,as the tfmr's should still step the AC voltage from the oscillator up to drive the lamps.Have spent all afternoon trying to trace the proper value,and they seem as scarce as hens teeth.

[Radio Fox]

Re: Royer Oscillator Question

Can't even see any on eBay.

As Toasty says, you could always connect 2 in parallel. Can you find a 0.047uF (47nF) in the same series & connect it in parallel with a 0.22uF?

Is that 250v dc, or ac?

[Rtech]

Re: Royer Oscillator Question

It is DC..Phillips/Visay MKT370 range,have them...but still no luck trawling the net.