Why a starter is used in a tube light?

Tube light requires two things to function. Very high starting voltage, and high voltage to continue the operation . The starter is a circuit which breaks at regular intervals . When you break a circuit and start again, high voltage spark takes place. This voltage is further amplified through the choke which is a transformer . Thus at the beginning the starter gives high voltage sparks. Due to this the current begins to flow through the tube and the tube begins to glow. Once the tube starts, the required voltage to sustain is quite low, which is provided by the choke. If the starter is bad the tube does not start . If the choke is bad or if the gas is low, the tube does not sustain its light .