How does 5 1 single chip microcomputer control the luminous intensity of 12 fluorescent lamp powered by 220V mains?

Dimming of fluorescent lamps is not recommended.

It will seriously damage the filament life of fluorescent lamps. Generally, the electronic ballast of fluorescent lamp works in a continuous working state, and your voltage is reduced. Ballast is also a rectifier filter, and the circuit is forced to increase or decrease the pulse width to meet the working requirements of fluorescent lamps. So the effect is not obvious.

If you must change the light intensity, because you are a 12 group of fluorescent lamps, each group should be broken down into several low-power fluorescent lamps. These fluorescent lamps are staggered. As long as you turn off some fluorescent lamps, the light will dim. You can adjust the light by turning off the number of fluorescent lamps, which not only achieves the goal, but also does not affect the service life of fluorescent lamps.