"William R. Walsh" m writes:

Hi!

I have a few questions:

What is going on?

See my other reply. Do you have a light switch that glows when you turn it
off? This will place a small amount of current flow across the lamp, which
may make it flicker.

Will it wear out the bulb very fast?

It may result in a slight amount of wear on the bulb, but I doubt the change
in lifetime would ever be noticed.

This I wouldn't be so sure of. Startup is hard on fluorescent lamps.

What is inside these bulbs? A rectifier? A capacitor?

In many cases, these bulbs contain a small switchmode power supply. Such a
power supply will have a transistor, some type of controller, a small
transformer and some support components (of which a capacitor would probably
be included). Others use a much simpler transformer design.

The transformer design will not experience this phenomenon.

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On 25 Jun 2007 20:29:58 -0400, Sam Goldwasser
put finger to keyboard and composed:

"William R. Walsh" m writes:

Hi!

I have a few questions:

What is going on?

See my other reply. Do you have a light switch that glows when you turn it
off? This will place a small amount of current flow across the lamp, which
may make it flicker.

Will it wear out the bulb very fast?

It may result in a slight amount of wear on the bulb, but I doubt the change
in lifetime would ever be noticed.

This I wouldn't be so sure of. Startup is hard on fluorescent lamps.

I recently had two lamps (EDAPT 20W) fail in a relatively short time.
Curiosity got the better of me so I cracked them open to have a look.

Lamp A lasted about 3 months, lamp B about one week. Lamp A had an
open filament, and both had open "startup" resistors. Lamp B would
start when it was cold (or completely discharged?) but would not
restart just after it had been switched off. Lamp A would flash
briefly if I tapped it, despite the resistor being open. I'm wondering
whether the failure in the resistor caused the premature burnout of
the filament? If so, then this would be in line with your comment re
startup "trauma".

BTW, I repaired lamp B and it has been working ever since. I should
also mention that lamp A was full of dry solder joints which may have
contributed to its early demise.

- Franc Zabkar
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