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How Does Tube Light Work And How To Install It

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A tube-shaped fluorescent lamp is commonly referred to as tube light. These are the oldest, albeit, still the most commonly used lighting system in Indian households. However, most of us may not be aware of the working of the tube light or how to install them.

This article helps you understand the working of the tube light. It also has a detailed step by step guide that walks you through installing the tube light yourself.

How does tube light work?

There are seven different components used to build a light bulb namely,

  1. Glass bulb coated with phosphor
  2. Filament coils
  3. Inert gases
  4. Mercury drop
  5. Electrode shield
  6. Glass stem
  7. End gap

Additionally, there are two other components – ballast and starter, that help the tube light to work properly. The ballast can be either electronic or electromagnetic. The starter is a tiny lamp that is filled with neon or argon gas. It contains a bimetallic strip, and a capacitor.

How does tube light work

  • When the power switch of the tube light is turned ON, voltage will flow across the tube through the ballast and starter. The lamp does not emit any light as there is no discharge within the lamp.
  • When the starter gets warm enough, it establishes a glow discharge. This happens as the distance between the electrodes is much lesser in the neon bulb of the starter than in the tube light.
  • The voltage ionizes the gas present inside the tube and causes the bimetallic strip to heat and connect with a fixed contact. This causes the current to flow through the starter.
  • Once the current flows through the tube, there is a drop in voltage, causing the bimetallic strip to cool down and break away from the contact.
  • When the strip breaks, there is a large voltage surge which strikes the gas mixture of argon and mercury vapor.
  • The process of gas discharge continues which clears a path for the current to flow freely through the tube light. At this point, the resistance in the tube is less than the resistance in the starter.
  • Mercury atoms discharge to produce ultraviolet light. The inner surface of the tube light is coated with phosphor.
  • When this UV radiation falls on the inner surface, it excites the phosphor coating that radiates visible light. Once the tube light emits light and becomes operational, the starter becomes inactive.

How to install tube light?

Installing a tube light is a simple and straightforward process. It can be done by anyone, even by someone who has no knowledge of electrical circuits and appliances. However, there are certain things that you need to keep in mind while installing tube lights.

How to install tube light

Ensure the power switch if Off

First and foremost, you should turn off the switch that supplies power to the tube light. You can also cut off the power supply using the fuse box just to make sure that there is no supply of current. Additionally, you can also use a voltage tester to detect the current flow.

Arrange for a ladder

Most likely, you won’t be able to reach the tube light fixture by standing on the ground level. You would need the support of a ladder to give you the desired height. Ensure that the base of the ladder or the support is stable and won’t get tilted.

Rotating the tube

If you are replacing the worn-out tube light with a new one, you first need to remove that. Rotate the tube to release it from the prongs and remove it from the fixture in a sliding motion.

Place the tube safely

Once you have removed the old tube light, hand it over to someone else or place it on a plain surface so that it doesn’t rollover.

Fix the new tube in the fixture

Similarly, take the new fluorescent bulb and fix it into the prongs and rotate it. Once it is in position, push it gently into the socket and it will get locked in. Gently agitate the tube to ensure that it is firmly locked.

Test the new light

Once you have installed the new tube light, turn on the main power to check if it lights up properly. Generally, tube lights take a minute or two to emit bright light.


Learning how to install a tube light comes in very handy. Even if you are not someone who is good with electrical appliances, you can easily fix a tube light. Instead of calling a technician, you can refer to our article and get it installed easily within a few minutes.

We hope that you were able to install your new tube lightly safely and smoothly with the help of our instructional guide. If you are facing any difficulties, let us know in the comment section and we will help you resolve it.

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