T8, T5, T4 tube and LED tube specifications, length and power

Specification diameter

Commonly used are T8, T5, T4 lamps, and T10, T12. Then, the “T” stands for “Tube”, which means that this thing is tubular, and the number behind the T indicates the diameter of the lamp.

Each “T” is 1/8 inch, an inch is equal to 25.4 mm. then each “T” is

25.4 ÷ 8 = 3.175mm, then the diameter of the T8 lamp is 25.4mm.

The diameter of the T12 lamp is (12/8) × 25.4 = 38.1 mm

The diameter of the T10 lamp is (10/8) × 25.4 = 31.8mm

T8 lamp diameter is (8/8) × 25.4 = 25.4mm

(T8 is just the diameter of an inch lamp)

T5 lamp diameter is (5/8) × 25.4 = 16 mm

T4 lamp diameter is (4/8) × 25.4 = 12.7 mm

Other lamp diameters in this order.

T3.5 diameter 11.1 mm

T2 diameter 6.4 mm

Length and power

Length of T8 lamp (Note: uniform width 39mm, height 52mm)

20w length 620mm;

30w length 926mm;

40w length 1230mm;

Length of T5 lamp (Note: uniform width 23.5mm, height 39mm)

8w long 310mm;

14w length 570mm;

21w long 870.5mm;

28w long 1170.5mm;

35w length 1475mm;

Length of T4 lamp (Note: Uniform width 21mm, height 32mm)

8w long 341mm;

12w length 443mm;

16w long 487mm;

20w long 534mm;

22w long 734mm;

24w length 874mm;

26w length 1025mm;

28w is 1172mm long;

What is the difference between T5 and T4, T8? Theoretically, the thinner the lamp, the higher the efficiency, that is, the same wattage lighter.

In order to save costs, T5, T4 are sold in the form of miniature brackets, that is, the ballast contained in the miniature space inside the bracket.

The efficiency and quality of such ballasts are generally not very good, resulting in the lamp should be very high efficiency but not as bright as the conventional T8 lamps, life is also a bit discounted.

Nevertheless, the actual use of thin lamps is easy to conceal, and the use of flexible occasions, which is why T5, T4 light tubes get the most designers to use them.

Commonly used lamps and characteristics of the family

Commonly used in households:

20W: length 64cm 640mm

30W: length 96cm 960mm

40W: length 128cm 1280mm

Color temperature.

Color temperature is expressed in terms of absolute temperature K.

Different color temperatures will cause people in different emotional responses.

Color temperature three categories.

a. Warm light: warm color light color temperature below 3300K, Warm light is similar to incandescent light color, the red light component is more, giving people a warm, healthy, comfortable feeling.

Suitable for families, homes, dormitories, hospitals, hotels, and other places, or where the temperature is relatively low.

b. Warm white light: also called intermediate color, it’s the color temperature between 3300K-5300K. Warm white light soft light, so that people have a pleasant, comfortable, peaceful feeling.

Suitable for stores, hospitals, offices, hotels, restaurants, waiting rooms, and other places.

c. Cool light: also known as daylight color, its color temperature is above 5300K, the light source is close to the natural light, there is a bright feeling so that people concentrate.

Suitable for offices, conference rooms, classrooms, drawing rooms, design rooms, reading rooms in libraries, exhibition windows, and other places.

The higher the color temperature, the closer to blue luminous flux is low. In fact, the total energy of the spectrum is not low, the lower the color temperature is closer to red.

It can be simply understood that the higher the color temperature (bluish), the shorter the wavelength (below 555nm),

the less sensitive the human eye is to light. And the luminous flux is related to the human eye perception. The less light received by the human eye, the lower the luminous flux.

For example, T5 is an energy-saving lamp, most of which is commonly close to daylight color, and T8 is an old fluorescent lamp, most of which is the commonly warm light.

The symbols that appear in the lamp

In addition to the above basic understanding of lamp parameters, the symbols printed on the fluorescent tubes in China, in addition to the brand logo and serial number of each manufacturer or distributor

The symbols that often appear include those indicating the type of fluorescent lamp, the diameter of the glass tube and the color temperature, etc. The meanings are as follows.

1) Symbols indicating the type of fluorescent lamps

YZ: indicates ordinary straight tube fluorescent lamp (Y – the first letter of “fluorescent lamp” Hanyu Pinyin, Z – the first letter of “straight” Hanyu Pinyin)

YK: indicates fast-start fluorescent lamp (K – for “fast start”)

YS: indicates instant start fluorescent lamp (S – for “instant start”)

YG: indicates the high-frequency fluorescent lamp

YDN: indicates single-ended internal starter fluorescent lamp

YDW: indicates single-ended external start fluorescent lamp

YH: indicates ring fluorescent lamp

YPZ: indicates self-ballasted fluorescent lamp for general lighting

D: electronic type (inductive self-ballasted lamp symbols omitted)

Note: The foreign (IEC) representation method is: PS: Preheat start

RS: fast start, S: hot cathode single pin type instant start. Such symbols are commonly used for foreign products.

2) Symbols indicating the diameter of the lamp’s glass tube

TX is used to indicate the diameter of the lamp’s glass tube. Among them, T: refers to the tube-type glass tube; X: refers to the diameter of the glass tube, for X / 8 inches.

Example: T12 indicates that the diameter of the glass tube is 12/8 inches. At present, the domestic model naming can be used directly in the metric size of the glass tube diameter.

(3) The symbol of the color temperature of the lamp

RR: daylight color (color temperature 6500K)

RZ: neutral white (color temperature 5000K)

RL: cold white (color temperature 4000K)

RB: indicates white (color temperature 3500K)

RN: warm white (color temperature 3000K)

RD: said incandescent color (color temperature 2700K)

(4) other symbols

CE: indicates that the radio interference meets the requirements.

In addition, the lamp will also have the rated voltage and power, and other technical parameters.

For example T8YZ36RR: indicates a tube diameter of 1 inch, power 36W, daylight color ordinary straight tube fluorescent lamps.

(Such as direct metric size to indicate the diameter of the glass tube, the above example can also be marked as YZ36RR26, indicating a tube diameter of 26mm.)

LED lamp


8w:30*600mm 174 beads 60 ml

12w:30*1168mm 276 beads 1000 ml

15w:30*1198mm 342 beads 1200 ml


LED fluorescent lamps and traditional fluorescent lamps in appearance size caliber are the same, the length of 60cm and 120cm, 150cm three


Its power is 10W, 16W, and 20W respectively, while the actual power consumption of 18W traditional fluorescent lamp (inductive ballast) is about 26W and 36W traditional fluorescent lamp (inductive ballast) is about 45W.

8W LED fluorescent lamp is equivalent to 20W ordinary fluorescent lamp illumination, 15W LED fluorescent lamp is equivalent to 40W ordinary fluorescent lamp illumination,

the same lighting efficiency as the traditional fluorescent lamp energy saving 80%;

Installation method.

LED fluorescent lamp installation is very simple, the installation of the original fluorescent lamp will be removed and replaced with LED fluorescent lamp,

and the ballast and glow starter will be removed, so that 220V AC mains power can be added directly to both ends of the LED fluorescent lamp

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