The Instant Start Circuit of Fluorescent Tube

The Instant Start Circuit of Fluorescent Tube Points : the instant start circuit of fluorescent tube The use of instant start for the tube is felt where the tubes are fixed to inaccessible position and where maintenance for the starter and the tube is difficult. For such a circuit an auto-transformer is required, the primary of which is in parallel with the main supply and the secondary is connected to the electrodes of the tube. When the tube is switched on, the auto transformer supplies heating current to the electrodes and when the electrodes are sufficiently heated, the high voltage of the transformer strikes the tube at that instant. Just after starting the voltage across the electrodes is brought to normal by the choke. The starting is helped by the capacitance between the lamp and earthed conductor as shown in Fig.