Preheaters ? Do you think about starters ?
If yes, I'm surprised, that 36W T8 is able to start without starter :
Starter is not a magic: It's only a device (voltage controlled timed switch; with limited life, so need to be replaceable), what ensure the combination of electrode temperature and peak voltage is present for the ignition.
The "preheat" circuit ensure it by first closing starter contacts,preheating electrodes and then create the HV pulse be the contact opening.
In Europe the preheat concept allow the use of simple series choke as a ballast, what is not as heavy, reliable, nice to the lamp (low crest factor) and has quite low losses (mainly, because the total VA's the winding has to serve is quite low - for F36T8 it is only ~90VA), so that's why it is virtually the only concept used for virtually all lamps in 230V areas.
If the ballast ensure same conditions by another means, the starter is then not used:
- Instant start uses OCV so high, the lamp ignite even with cold electrodes. But this high OCV would mean, then the transformer is necessary (~700V for F36T8), so the total winding VA's to handle would be (again for F36T8) about 400VA, so it would be about 4x bigger and 4x more lossy then the series choke, what is the major reason for it not being used. Moreover it has low cyclic life, as it start the discharge at cold electrodes. Used only where only 2-terminal lamps were necessary (explosion proof sockets - making them for more then one contact per each side was difficult)
- Rapid start heat filaments by low voltage supply, what heat them up, so the OCV for the lamp to start does not have to be so high, ~400V suffice for F36T8, what yield to lower total VA's then the instant start, but still quite high, or it has to use mainly capacitor to ballast the lamp, what has high crest factor, so stress electrodes. It has been used in the form of a "resonant - start", where it used resonance to boost up the voltage (note, then this concept is the base operating principle of all HF electronic ballasts used today).
Beside this it is quite complex circuit, what in the view of higher losses, necessity to use 4-pin lamps and generally poor starting reliability mean it has no real advantage for 230V area.
