Balanced circuit

[[File:transformer balance.svg|thumb|300px|”’Fig. 5.”’ Balanced line connected by transformers.]]

[[File:transformer balance.svg|thumb|300px|”’Fig. 5.”’ Balanced line connected by transformers.]]

[[File:electronic balance.svg|thumb|400px|”’Fig. 6.”’ Balanced line connected to electronically balanced circuitry.]]

[[File:electronic balance.svg|thumb|400px|”’Fig. 6.”’ Balanced line connected to electronically balanced circuitry.]]

[[File:impedance balance.svg|thumb|350px|”’Fig. 7.”’ Balanced line connected to an asymmetrical signal, but with balanced impedances.]]

[[File:impedance balance.svg|thumb|350px|”’Fig. 7.”’ Balanced line driven with an asymmetrical signal, but connected to balanced impedances.]]

There are a number of ways that a balanced line can be driven and the signal detected. In all methods, for the continued benefit of good noise immunity, it is essential that the driving and receiving circuit maintain the impedance balance of the line. It is also essential that the receiving circuit detects only differential signals and rejects common-mode signals. It is not essential (although it is often the case) that the transmitted signal is balanced, that is, symmetrical about ground.

There are a number of ways that a balanced line can be driven and the signal detected. In all methods, for the continued benefit of good noise immunity, it is essential that the driving and receiving circuit maintain the impedance balance of the line. It is also essential that the receiving circuit detects only differential signals and rejects common-mode signals. It is not essential (although it is often the case) that the transmitted signal is balanced, that is, symmetrical about ground.