Definition

• A circulator is a transmitting device made with three different ports that allows electricity to flow in specific directions based on which port it enters or exits. It is usually made with three different arms, each at a 120 degree angle to the others, although some may have more than three ports. While circulators are traditionally used with electricity, they are also made to function with microwaves, light, and other types of energy.
  
  

Process

• Circulators are made to channel electricity into the next available slot. If electricity passes through the first port, it will exit through the second, with little electricity escaping through either the third or back through the first. Electricity going into the second port will exit from the third, and so fourth, with electricity entering the last port leaving through the first. This type of frequency control allows for greater control of the signals in use, and lets one device both send and receive signals to different components.
  
  

Materials

• Circulators are made of ferrite materials, or materials that react in specific ways to magnetism. When charged correctly, the ferrite materials will bend the signal in a particular direction. The charge is usually given via a permanent magnet that is connected to the bottom of the circulator, and can be set to channel the signal either clockwise or counterclockwise.
  
  

Uses

• Electronic circulators are used primarily in systems that have antennas, since signals can be sent from a specific device to the antennae, and when the antennae picks up signals it can send them back through the same channel to a different device. In similar ways, other types of circulators are used for data transfer, such as fiber optic channels.
  
  

Isolators

• Sometimes one port of the tri-port circulator is block, so that signals can only go one way. This makes an isolator, which is used to preserve signals from interference when incoming and produce signals with greater clarity when outgoing.