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Fluorescent tubes are fitted with a choke. The choke coil
Explanation
In fluorescent tube circuits the choke (ballast) is an inductive device whose primary role is to limit the current through the lamp once the discharge is established. Ballasts/chokes prevent the lamp from drawing excessive current (a near-short when ionized) by providing inductive impedance at mains frequency, thereby reducing and stabilizing current flow [1]. During starting, ballasts can help produce the higher voltage needed to strike the arc, but after ignition they restrict current to safe operating values; electronic ballasts similarly produce a high starting voltage and then regulate/limit current during operation. Thus the choke’s key function in traditional tube fittings is current limitation rather than stepping down line voltage or filtering low-frequency currents.
Sources
- [1] https://edisontechcenter.org/Fluorescent.html