Tube Circuit with Glow Signing Switch

Tube Circuit with Glow Signing Switch Points : tube circuit with glow signing switch In Fig. when the switch S is dosed, the fall voltage is applied across the starter bimetallic strips and the normal supply voltage is sufficient to start a glow across the starter terminals, i.e., for that period for which the glow persists, the tube cathodes are short circuited and are heated up. At the same time, the glow across the bimetallic strips heat them up and so they are bent and the glow disappears, i.e. the circuit breaks. This sudden interruption of the current in the inductive circuits causes high voltage to appear across the tube electrodes ‘which is sufficient to start the discharge in the fluorescent tube. A small condenser C₁ across the two bimetallic strips suppress the radio interference generated by the lamps. The condenser C across the supply mains is for improving the power factor. Fig represents the internal view of the starter, while Fig. represents a circuit with the tube in position.