Electronic Pulsestarter fluorescent tube starter.

Modern fluorescent tubes have so little mercury vapour in them that sometimes they do start with a purple glow in the middle (carrier gas colour) until the mercury has heated and distributed through the tube.

Big Clive

I think they all do that, until they get up to temperature

Paul Ferguson

Re: Electronic ballasts... Why is it, when using an electronic ballast, the tube glows brightly at each end, dim in the middle, then after a few minutes the whole tube glows?

Oh interesting. So is it the tubes failing, or a loose ground/missing to the fixture? Or both? :)

Ryan Stasel

For reliable starting fluorescent tubes require a grounded plane in their vicinity. It has a capacitive coupling effect. You used to be able to get tubes with a conductive strip along one side for specialist applications.

Big Clive

I swear you've answered this before Clive, but question. Why do you occasionally have tubes that don't start (just glow) until you touch it? Are you somehow capacitively coupling to ground (pretty terrible ground)?

Ryan Stasel

I wonder if it having a non smoothed DC ripple on the circuit has something to do with the way it works? They operate for a second or two but does it switch on and off at mains frequency x2 during this period?

Paul Ferguson

I remember seeing those start buttons (or switches that had an extra depth to their travel, spring loaded) on hand-held fluorescent lights and smaller desktop lights, particularly the circular ones with the magnifier in the middle.

Dustin

It's a very "classic" look. Particularly if the tube is failing to strike. The first lights had a manual starter switch that you had to hold in the start position to start them. It was combined with the on-off switch.

Big Clive

There's always something I liked about the old multi-strike starters. Like they had to work a bit harder.

The Griffiths Family

There's one way to find the value of that capacitor, and that's to test it with my tongue.

Al Hunt