Capacitor in the fluorescent light ?

If the capacitor is across the AC line, it's likely to limit radio interference. If the capacitor is on the DC side of a rectifier, it would keep the light from flickering. And, of course, there's LOTS of other ways a capacitor could be part of a fluorescent lamp circuit, like DC blocking (to prevent erosion of the lamp's filament).

The capacitor is for power factor correction, It is not required for correct or safe operation of the light. There may be a legal or contractual requirement for it to be present.

"Jasen Betts"

Google sheep alert !!!

Very misleading, actually.

.... Phil

Cos phi corrcction.

Power factor correction for mere mortals ;^)

I'd be a bit worried about that oil, may contain nasty PCB (?) poison if it's an old fitting, 'cos they stopped using oil-filled caps in that function decades ago. These days a polycarbonate cap would be placed in there, across the line (X rated cap).

There's no DC side to a 40W fluorescent lamp circuits I've seen, did manufacturers ever care about the lamp's filament? But maybe in AU with 240V mains we have a different common circuit for the old fluoros?

It is common to see one side of the tube to go black, I had a 15W desklamp put so much DC through the tube the ballast burned the bench top black, where the lamp was used.

Grant.

Thanks to all members for the response