4-20mA Current Loop Output

4-20mA Current loop output is a type of electrical signal that is used in a series circuit to provide a robust measurement signal.

The sensor or instrument generating the signal acts like a current source providing a constant current output signal for a given measurement independent of supply voltage or circuit impedance.

Unlike voltage outputs, the current output is the same at any particular point in the circuit and is a relatively high power analogue output which can be used in measurement circuits over long distances.

A typical current output is 4 to 20 mA in a 2 wire configuration, but there are 3 wire configurations which can provide 0 to 20mA or 4 to 20mA current loop output signal with a separate positive supply and output connection.