Incandescent lamp is also called tungsten lamp. The filament temperature of a lighted incandescent lamp is as high as 2000 degrees Celsius or higher. Incandescent lamps are the closest to sunlight, and they are cheap and have good color rendering. The color rendering index is 99 to 100. Color rendering index is an indicator of color authenticity. Generally, the higher the color rendering index, the closer the color of the object is to the real color.

It is precisely because the hot filament produces light radiation that the electric lamp emits bright light. Incandescent lamp is a heat radiation source.

There are many kinds of incandescent lamps, which can be divided into socket type and screw type according to the structure of lamp holder, and six types according to the rated voltage, such as 6, 12, 24, 36, 10 and 220V. According to the purpose, it can be divided into incandescent lamps for general lighting, incandescent lamps for projection, low-voltage safety lamps, infrared lamps and various signal indicator lamps.

The shapes of bulbs with different rated voltages are very similar, so when installing and using bulbs, it should be noted that the rated voltage of bulbs must be consistent with the line voltage.