What exactly is LED starter?
The producers ship it with only a vague explanation that it is needed to replace the original fluorescent tube starter when replacing the fluorescent tube with its LED doppelganger, but they never explain what it is inside and how exactly it works.
If you crack it open, you will only find a fuse or short inside it.
The “starter” is a technical misnomer as everything needed to start a LED tube replacement for a fluorescent one is already inside the tube. In order to retrofit it into an existing armature, the starter needs to be replaced with a short (or fuse, depending on local rules). Without it, there is no voltage available to the LED tube driver and with a regular starter, there is nothing to emulate the filament inside the tube to make it flip over, save for a few very specialized LED tube replacements.
Best guess is that they decided to call it a starter to feel familiar with what they are replacing.
The circuit of an old-style florescent fixture with a starter is like this (image from here - corrected by myself):
The conventional starter is a special discharge tube with a bimetal switch inside. Image from this video:
When the fluorescent tube is not ignited the voltage across it is high, so the starter gas discharge tube ignites and heats the bimetal so it shorts and then heats the filaments at each end of the tube. That stops the heating of the bimetal so it will release in a short time. Once the filaments are sufficiently heated, there's enough emission to sustain a discharge and they self-heat and the starter can release until the power is cycled. Sometimes it takes a few 'tries' to get the tube to light.
In some cases, they replaced the starter switch with a momentary switch for manual operation (eg. for magnifier circular lamps).
So as you can see there is power available from one end of the tube to the other, even without the starter, so what's up with doing anything with the starter, you may ask.
LED lamps have electronics incorporated and it's inconvenient to run a wire the length of the tube so it would be more convenient to pack the power supply into one end and short the starter socket so that both sides of the power are available on either end. Also if they shorted both ends of the filament pins and drew power from them, it might do something rather unpleasant if the normal starter was still installed (and a percentage of DIY'rs are going to do dumb things).
At least that's my assumption.
Why do they call it a 'starter'? The LED won't work without it, so it must be a starter..
