Electrical World

Design: A fluorescent lamp consists of a sealed glass tube filled with an inert gas (usually argon) at low pressure. On each side of the tube you will find a tungsten electrode. Both these electrodes are wired to an electrical circuit, which includes a starter and ballast, is hooked up to an alternating current (AC) supply. The tube also contains phosphor powder, coated along the inside of the glass. Working: When the lamp is first turned on, the current cannot pass through the tube initially because the gas inside it is not ionized and hence the tube light circuit acts as an open circuit. The current travels through the path of least resistance, which is through the bypass circuit, and across the starter switch. This current then passes through the circuit heating up the filament in each electrode, which are located at both ends of the tube (these electrodes are simple tungsten filaments, like those found in incandescent light bulbs). This boils off elect...