What is the function of choke in tube light?

Short Answer:

The choke in a tube light is an inductor (ballast) that helps in the starting and operation of the fluorescent lamp. It provides a high-voltage surge to ignite the gas inside the tube and then regulates the current to prevent excessive power consumption.

Without the choke, the tube light would not start properly and could get damaged due to high current flow. It works alongside the starter to create the necessary high voltage and then limits the current to ensure stable operation of the lamp.

Detailed Explanation

Function of Choke in Tube Light

A fluorescent tube light operates using a gas discharge process, which requires a high-voltage pulse to start and a regulated current to operate efficiently. The choke (ballast) plays a crucial role in both starting and running the tube light.

1. Provides High Voltage for Ignition

1. • The tube light contains gas (mercury vapor) and electrodes at both ends.
   • Initially, the starter creates a brief closed circuit, allowing current to flow through the choke and electrodes.
   • When the starter opens, the sudden interruption of current causes the choke to generate a high-voltage pulse (around 1000V to 1500V).
   • This high voltage ionizes the gas inside the tube, creating a conductive path for electricity to flow and generate light.

2. Limits and Regulates Current

1. • Once the tube light starts, it behaves like a low-resistance path, and without a current limiter, it would draw excessive power, leading to damage.
   • The choke acts as an inductor, opposing rapid current changes and keeping the current at a safe level.
   • This ensures stable and efficient operation of the tube light.

3. Prevents Flickering and Enhances Lamp Life

1. • The choke smooths out fluctuations in current, preventing flickering.
   • By controlling the current, it reduces stress on electrodes, improving the lamp’s lifespan.

Types of Chokes Used in Tube Lights

1. Electromagnetic Choke (Conventional Ballast)

1. • Made of copper windings on an iron core.
   • Works based on inductive reactance to control current.
   • Slightly heavy and inefficient, but commonly used in older tube lights.

2. Electronic Choke (Electronic Ballast)

1. • Uses electronic circuits to generate high-frequency voltage.
   • More energy-efficient and eliminates flickering.
   • Reduces power consumption and heat loss, making it widely used in modern tube lights.

Conclusion

The choke in a tube light is essential for both starting and controlling current flow. It generates the high-voltage pulse required to ignite the gas and then limits the current to ensure stable operation. Modern tube lights use electronic chokes for improved efficiency and reduced energy consumption.