Where is Fillament of a tube light present?

Answer 1

on a 4 pin tube there is a small filament at each end cap, this coil connects the 2 pins on one end together (and there is a second filament coil at the other end).

the filament warms the tube, which makes it easier to strike (turn on). the following diagram should help (labels in spanish)
http://en.wikipedia.org/wiki/Image:Fluorescente.png
Filamento = filament
reactancia inductiva = inductive resistance (ballast)
cebador = starter
condensador = capacitor
contacto bi-metallica = bi-metallic contact


http://en.wikipedia.org/wiki/Flourescent_tube

Answer 2

there is no filament in tubelight