Who is brightest ?

[mowhoong]

A 20 watt home fluorescent light, is allway brightest than a 20 watt
fluorescent light which is operate by 12 volt car battery dc to ac
converter.
Can any person know ?

 

[The Real Andy]

A 20 watt home fluorescent light, is allway brightest than a 20 watt
fluorescent light which is operate by 12 volt car battery dc to ac
converter.
Can any person know ?

20watts is the power consumption, not the light output. Some forms of
lighting are more efficient than others, that is some output more
light per watt of power consumption than others.

 

[Art]

Also very dependent on the type of ac signal applied. A lot of converters
do not produce a pure sine wave and the efficiency therefore suffers.
Dissipated wattage measured may be the same. Also the lux output of the
lamps will vary due to specific design.

 

[LASERandDVDfan]

A 20 watt home fluorescent light, is allway brightest than a 20 watt

fluorescent light which is operate by 12 volt car battery dc to ac
converter.
Can any person know ?

Fluorescent lights are not like incandescent lamps. While the wattage in an
incandescent lamp can determine brightness, wattage determines power
consumption of the ballasts with fluorescent lamps. In fluorescent lights,
wattage has nothing to do with total light output.

Amperage, however, might. You are going to have better amps from house current
than from a DC battery running an AC converter.

It all depends on how well the ballast will allow the tube's electrodes to arc
across the gas inside, manipulating the electron orbit of atoms of mercury
vapor in the tube to generate UV light, which excites the inner phosphor
coating on the glass which makes it fluoresce.

How well the ballast may work to do all this to generate the UV light depends
on its condition and the power quality. - Reinhart

 

[mowhoong]

Also very dependent on the type of ac signal applied. A lot of converters
do not produce a pure sine wave and the efficiency therefore suffers.
Dissipated wattage measured may be the same. Also the lux output of the
lamps will vary due to specific design.

Thanks all for the informamtion,Art got the point , that is something
to do with the freq. For those study table lamp operat by converter
the output freq.
are very hig, I forgot what is the freq.When I bough the second set
the mfe.deleate the freq.row

 

[James Sweet]

Fluorescent lights are not like incandescent lamps. While the wattage in an
incandescent lamp can determine brightness, wattage determines power
consumption of the ballasts with fluorescent lamps. In fluorescent lights,
wattage has nothing to do with total light output.

It's not that it has nothing to do with light output, it's just that the
light output varies a lot more for the given wattage. A fluorescent tube's
brightness is determined by how high the drive current is, the wattage
rating on the tube is the nominal wattage for which it's designed, you can
drive them over or under wattage and get more or less light, however
lifespan and efficiency suffers past a relatively small range of current the
lamp is designed for.