It mainly provides people with electric energy and converts it into other energy sources, such as air conditioning electricity, lighting electricity, power electricity and so on.
Extended data:
Commonly used building weak current systems mainly include the following:
(1) telephone communication system
Realize the communication function of the telephone (including three types of fax machines, videophones, etc.). ); Star topology; Using three (or more) unshielded twisted pairs, the frequency of the transmission signal is in the audio range.
(2) Computer local area network system
It is the network foundation to realize office automation and various data transmission; Star topology; Five types (or more) unshielded twisted-pair wires are used to transmit digital signals, and the transmission rate can reach more than100 MB/s.
(3) Music/Broadcasting System
Music can be played through loudspeakers installed on the site (such as shopping malls, stations, restaurants, guest rooms, corridors, etc.). ), and the scene can be broadcast through a microphone; Multi-channel bus structure; Constant voltage audio signals (such as120v120Ω) output by the power amplifier are transmitted to drive the on-site speakers to sound, and the transmission line adopts copper core insulated conductor.
(4) CATV signal distribution system
Distribute CATV signals evenly to all user points in the building; Branches and distributors are used for signal distribution. In order to reduce the signal distortion and attenuation, and make the signal quality of each user point meet the requirements specified in the specification, the wiring is tree-shaped and changes with the form of the building and the distribution of user points. Using 75 Ω RF coaxial cable to transmit multi-channel RF signals.
(5) Video monitoring system
Monitor the entrances and exits of buildings and some important places through cameras, burglar alarms and other equipment installed on site, and give an alarm if there is any abnormality; The transmission of video signal adopts star structure and uses video coaxial cable; The transmission of control signals adopts bus structure and uses copper core insulated cable.
(6) Fire alarm system
References:
Baidu encyclopedia-weak current engineering