With the continuous improvement of new technology and the continuous application of big data, intelligent engineering construction has gradually become a reality from a concept.

From the perspective of discipline division: electricity, electronics and electrical appliances are all electrical engineering disciplines. All electronic systems engineering below 110V.

(2) parallel cables between groups and between groups to dc distribution box (bus box). Connection of cables dc cables in the photovoltaic power generation system are mostly laid outdoors.

At present, urban rail transit can be divided into metro and light rail system. Heavy rail? Axle load? Japan's HSST and Germany's TR express are both normally-guided maglev trains.

In the field of automatic control, PLC is an important control equipment. At the same time, some also provide 24V power supply for the input circuit.