Is it possible to use fluorescent tubes wired in series, provided that the ballast can supply a high enough voltage and power?
F28T5 are too long (4ft) for me, so instead I plan to use pairs of F14T5 side by side, which are 2ft long. The problem is this would require more ballasts. Typically, one ballast can power one or two lamps, like so
My theory is that 2 x F14T5 would be electrically equivalent to one F28T5, if wired in series. The ballast will provide the appropriate current, which would be almost the same. Is this correct? or would the plasma have very different characteristics with an intermediate electrode?
Another potential problem is starting the lamp. My understanding is that the plasma in the tube must first be ionized, typically by heating a filament at both ends. But with lamps in series, the middle two filaments would be cold since they are not connected to the ballast.
Would this prevent the lamp from starting? or does it only need to be heated from one end? (Note that with two lamps in series, each lamp has one heated filament. But with three or more, the middle lamps will be cold. Would it also work with three or more lamps?) Would using a different type of ballast (instant start) that uses a high voltage to induce breakdown avoid this problem?