A Guide to Fluorescent Lamps

Fluorescent lamps are indispensable in modern life. In this article, we will explain how fluorescent lamps work, the types of light they produce, and how to read their part numbers.

How fluorescent lamps work


Fluorescent lamps are very common these days. Another common type of light fixture is incandescent lamps. The main difference between these two types of lamps is in how they emit light. Incandescent lamps emit light because of the electrical resistance caused by an electric current passing through bulb filament. Fluorescent lamps emit light when electricity flows through them but the mechanism is a little different. 

An electric current passes through mercury gas in a fluorescent tube coated with fluorescent paint. When the ultraviolet light hits the fluorescent paint, the fluorescent paint emits light. The reason why fluorescent paint is deliberately applied is that the mercury inside the fluorescent tube emits light much more efficiently than the bulb, and because the light is too strong, it is a necessary step to diffuse it.

Types of Lighting Methods


There are three types of lighting methods for fluorescent lamps: glow starter, rapid start, and inverter. Each has its own characteristics, which are explained in detail below.

Types of Lighting Methods

There are three types of lighting methods for fluorescent lamps: glow starter, rapid start, and inverter. Each has its own characteristics, which are explained in detail below.

Glow starter

The glow starter type is the most common lighting method. It uses a glow starter tube. Although there are some disadvantages - it takes 2 to 3 seconds to light up after the switch is turned on - it is widely used. This is because of its simple design and low price. Fluorescent lamps such as FL and FCL lamps are used for glow starters ( a separate glow lamp is required).

Rapid start 

This type uses a ballast with a built-in electrode preheating circuit and voltage booster circuit to light the lamp without the use of glow starters. In addition, the fluorescent lamp itself is equipped with a starting aid device to start discharging at a low voltage. Therefore, glow starters are not required, and the fluorescent lamps light up immediately upon switching on. This type of fluorescent lamp is widely used in stores, offices, and other commercial applications, and uses dedicated rapid lamps such as FLR fluorescent lamps.


The inverter type uses an electronic ballast (inverter) to convert commercial AC power once into DC and then into high frequency to light the fluorescent lamps. High-frequency lighting eliminates flickering and saves energy. No glow lamps are required and FHF fluorescent lamps are used, but their high price is a disadvantage.

Types of light

Daylight color

This is a cool white light color with a slight bluish tinge. It is often used in offices and offices. It seems brighter than daylight white for the same wattage.

Daylight white

It is white natural light. It is more bluish than midday sunlight. Used in offices and homes.


It is a warm light color with a slight yellowish tinge and gives a calm impression. It is used in offices, factories, and general households.

Warm white

Slightly reddish than white, this is a natural light. It is selected when the light bulb color is not bright enough. Used in living rooms and bedrooms in general households.

Light bulb color

This color is reddish and reproduces the color of incandescent light bulbs with fluorescent lamps. The light bulb color has a restful and calming effect on people, but it is not suitable for places where brightness is needed, such as work tables and study desks. They are used in the living rooms and bedrooms of ordinary homes.

How to read the model numbers of fluorescent lamps


Fluorescent lamps can be used even if they are made by different manufacturers, as long as the lighting type and tube length (wattage) are the same. There are many factors you can refer to when trying to read the model number.

Let us look at an example of a general fluorescent lamp model number.


Here is a breakdown of each component. 

Lighting type of fluorescent lamps

There are FL (straight tube/glow starter type), FLR (straight tube/rapid start type), and FHF (straight tube/high frequency only type).

Eg - lighting method - FLR (rapid start method)

Tube length (wattage) classification

40' (1198 mm), 110' (2367 mm), 20' (580 mm), etc.

Eg - tube length 40' (1198 mm)

Tube diameter (thickness)

SS (28mm), S (32.5mm), and H (high power) are available.

Eg - Tube diameter - S ( 32.5 mm)

Light color

D (daylight), N (daylight white), W (white), WW (warm white), EX (three-wavelength color), etc. The light color can be checked on the package.

Eg - W (white)

Rapid start type is indicated with 'M'; those without 'M' are glow starter type.

Eg - M (rapid start)

Power-saving specifications

Indicates power consumption.

Eg - 36W

In the case of additional functions or designated classification of each manufacturer

PC (with photocatalytic coating), NU (fade-proof type), P (shatterproof type), etc. are indicated by alphabetical characters.

In addition, some models are marked with 'EX' in the model number, while others are not. The differences are explained below.

'EX' in the model number: 3-wavelength

Used in showrooms and other places where color rendering is important. They are brighter and have a longer life than 1-wavelength lamps.

No 'EX' in the model number: General fluorescent lamps

This type is used in factories and other places where large quantities are used. Recommended for cost-conscious users.

 eg - no EX so general 

So to summarize, in the case of our example above, the model number FLR40SW/M/36

 can be read as below

Lighting method: FLR (rapid start)

Tube length: 40

Tube diameter: S (32.5mm)

Luminous efficacy: W (white)

Type: M (rapid start type)

Power consumption: 36W

No EX - general fluorescent lamp


Fluorescent Lamp Replacement Guidelines


After several to ten years of use, fluorescent lamps will begin to darken or blink. If any of the phenomena we are about to introduce below occur, please replace the lamp as soon as possible.

Anode spot

Black spots that occur on the surface of fluorescent lamps are called anode spots. If anode spots appear early, the following improper use may be the cause.

  1.  Lights are turned on and off frequently.
  2. Power supply/voltage is too high or too low
  3. Wrong type of fluorescent lamp installed.

End band

This is a blackish-brown color band that appears from the end of the lamp tube toward the center of the lamp.

When a lamp that has been left unlit for a long time is turned on, blackening may occur immediately after lighting, but this is not a problem because the blackening is caused by mercury adhesion. After lighting the lamp for a while, the mercury will evaporate due to the rise in lamp temperature, and the blackening will disappear.

How to remove fluorescent lamps

For straight tube fluorescent lamps直管蛍光灯の場合

There are three types of removal methods: turning the fluorescent lamp, pushing it to one side, and pulling the cover on both sides to the center.

Cylindrical fluorescent lamps

Simply remove the socket (the thickened part) and the surrounding metal fittings.

Long life and energy saving! Features of LED fluorescent lamps and how to replace them


Compared with conventional fluorescent lamps, LED fluorescent lamps are longer lasting and more energy-efficient, using less than half the power and lasting three times as long as conventional fluorescent lamps.


Framing Life

Freeze power

Conventional Fluorescent Lamp

13,000 time level

40,000 time level

LED Fluorescent Lamp


15W (average)

Replacing LED Fluorescent Lamps

The work differs depending on whether the fluorescent fixtures are used as they are or the entire fixture is changed.

When using the current fluorescent fixtures as they are

Construction required 

Advantage: Since no ballast is involved, LED fluorescent lamps can be used with the same specifications as indicated.

※ Please consult an electrician for installation.

No installation required 

Advantage: Easy installation.

※ *Non-installation type requires the selection of an LED fluorescent lamp that matches the lighting system of the fixture.

Fixture has a glow bulb

Inverter type

The fixture is not equipped with a glow bulb, and the type of stabilization period is marked with Hf.

Rapid start type

The fixture is not equipped with a glow bulb and the type of stabilization period is not marked with Hf.

Rapid start type

Change the entire fluorescent fixture

Purchase an LED fluorescent lamp (base light) with an integrated fixture.

There are also 'single-sided' types, which do not cause electric shock when installed, and 'double-sided' types, which can be installed in opposite directions and still light up.

Be sure to select the correct type, as incorrect usage or the wrong fixture may result in damage or malfunction.