Unshielded electronics, inverters, or other unwanted signals always result in common mode noise current and usually common mode choke is the excellent choice to filter/suppress these unwanted noises in electrical circuits to avoid the interference problem. The common-mode choke work like the filter in the circuit, it has two winding with a 1:1 turn ratio and could work in both normal or differential mode. As a common mode, the current will go through the two winding in the same direction. Hence the magnetic flux is boosted each other, which means the inductance will be generated to impede common mode current. On the other hand, the current travels from one line from the source to the load and returns in the opposite direction as the complete circuit. The magnetic flux is canceled and the current could pass directly, this is the differential mode.
Several reasons need to be considered when you choose the common mode choke, working frequency range (in a power line, normally is under 1MHz, for signal line, the working frequency will require up to GHz), current handling capacity (when current flow the coil, the heat will be generated, to control the temperature rise is crucial during designing stage), and require impedance/inductance.
Coilmaster Electronics produces a wide range of Common mode choke, Choke Coil, Power Choke, Common mode inductors in different construction. For instance, surface mount common mode choke for both power line and the signal line, through-hole common mode EMI chokes for power line, high-speed miniature common mode choke for the data line.