Why CFL lamps don't flicker and have spiral structure ?

Lets say a decade before, you were told to replace your old filament bulbs with that time favorite tube lights. You would surely hate the tube light and loved the bulbs for one sole reason that is flickering. The tube light may take even minutes to turn fully on and give a constant light dissipation. This was not there in bulbs even though they were inefficient in converting the electricity to light. So the main problem with the tube light was flickering. This was rectified in the new generation CFL's.

Why CFL lamps don't flicker and have spiral structure ?
Why CFL lamps don't flicker and have spiral structure ?

How it is different from the conventional tubelights and why does it not flicker when it is turned on?

Let's find out!!!

The Idea behind it :

Before we know why a normal CFL ( Compact Fluorescent Light ) does not flicker, lets snoop into its principal how it really works.

CFL's can be divided into two main parts. One is the ballast which can be magnetic or electronic, which is usually covered in a case. The second one is a gas filled tube, which you can easily see from outside.
To remove flickering we generally use electronic ballast instead of magnetic ballast because they are much faster and compact. 
Lets have an overlook of what electronic ballast comprises of. They contain a small PCB with rectifiers, a filter capacitors and generally two switching transistors. It follows the following steps:

1. Incoming AC current is first converted to DC.
2. It is then converted into high frequency AC by the transistors.
3. The resulting high frequency is applied to the tube.

Working :

The resulting high frequency excites the electrons inside the CFL which has mercury vapors and argon inside. It is also coated with phosphor. This gets illuminated when the electron falls on it. So larger the surface area it is coated, more faster will be its illumination time. The sharp edges at the spiral also boost up the speed of the electron thus accelerating it. Thus we don't see the CFL's flicker. This is not there in the conventional type of tube light.


  1. Since it uses mercury vapors, its disposal is not Eco-friendly.
  2. Since it is a point source rather than a line source of light like tubelight, the light intensity in all directions is not same. So near the CFL the intensity is more.