What does galvanic separation mean

Galvanic isolation - explanation and application

A short and easy-to-understand explanation of galvanic separation or decoupling and its application.

Galvanic separation, or galvanic decoupling, is an electrical separation between two conductive objects. Conductive objects are, for example, electrical circuits. With this separation, it is therefore not possible for the charge carrier in the circuit to get from one circuit to the other, or to flow, since the conductive, electrical connection does not exist and therefore no current can and will not flow through it.

Possibilities for a galvanic separation

  • The Italian Luigi Galvani (September 9, 1973 to December 4, 1798) was a doctor, anatomist, biophysicist and eponym of galvanic separation. Roughly, it denotes a non-existence or existence of a conductive connection.
  • Various components, such as optocouplers or capacitors and transformers, can be used to implement the separation. In these cases, the magnetic field takes a detour through the transfer of charge.
  • There is an inductive separation: Here, a separation from the mains is created during the voltage adjustment in order to establish safety in the connected circuits against touching the mains voltage. There is a capacitive separation, which means something like a charge shift. And there is information transmission that is possible through non-electrical transmission paths.

Areas of application

  • Galvanic isolation is used in the following examples listed below: On the one hand, for safety in electrical toys, all mains-operated low voltages, chargers or medical devices. Galvanic isolation is also used for metrological reasons, such as the power supply of measuring devices from the circuit.
  • But it is also used to prevent ground loops or electromagnetic interference. If several electrical quantities are to be measured and then recorded in a computer, whereby the potentials should differ, then, for example, the transducers must be galvanically isolated from one another. This can be achieved with isolation amplifiers, analog optocouplers or current transformers, among other things.
  • Correct application of galvanic isolation is also an efficient protection against electromagnetic interference. Of course, this is also the case when there is no connection to other circuits. Even long cables without a conductive power connection can pick up interference and pass them on to signal inputs. The protection against radiated electromagnetic waves is also improved by separating signal inputs.
  • All measures are summarized under EMC - electromagnetic compatibility. Galvanic isolation is also still required for remote data transmission on the high-voltage lines and for protection against electromagnetic pulses.