When the fluorescent tube is switched on almost full supply voltage is applied to the starter. The potential across bimetallic electrodes of the starter causes a small glow discharge at a small current not enough to heat up the tube FILAMENTS. This discharge is enough to heat the bimetallic strips of the starter itself causing them to bend and make contact. As a result, the large current flows through the electrodes their temperature being raised to incandescence and the gas in the immediate neighborhood inside the tube gets ionized. At the same time when the contacts of the starter are closed potential difference across it is REDUCED to zero. After two or THREE seconds glow discharge inside the starter stops and the bimetallic strips cool down which breaks the contacts apart. This sudden break induces a very high voltage in the coke connected in series due to its inertia EFFECT and it is sufficient to initiate the discharge in the main tube LIGHT. When the fluorescent tube is a light, current passes through the tube which offers a very low resistance. The voltage across the tube is about 110 volts and rest of the supply voltage of about 110 volts is dropped in the choke. Due to the low voltage, the starter ceases to glow. Starters are so designed that this potential difference across the lamp in running condition is insufficient to restart the glow discharge in the starter. So the contacts remain open, thus the tube is put in operation.

When the fluorescent tube is switched on almost full supply voltage is applied to the starter. The potential across bimetallic electrodes of the starter causes a small glow discharge at a small current not enough to heat up the tube filaments. This discharge is enough to heat the bimetallic strips of the starter itself causing them to bend and make contact. As a result, the large current flows through the electrodes their temperature being raised to incandescence and the gas in the immediate neighborhood inside the tube gets ionized. At the same time when the contacts of the starter are closed potential difference across it is reduced to zero. After two or three seconds glow discharge inside the starter stops and the bimetallic strips cool down which breaks the contacts apart. This sudden break induces a very high voltage in the coke connected in series due to its inertia effect and it is sufficient to initiate the discharge in the main tube light. When the fluorescent tube is a light, current passes through the tube which offers a very low resistance. The voltage across the tube is about 110 volts and rest of the supply voltage of about 110 volts is dropped in the choke. Due to the low voltage, the starter ceases to glow. Starters are so designed that this potential difference across the lamp in running condition is insufficient to restart the glow discharge in the starter. So the contacts remain open, thus the tube is put in operation.