Maxim Integrated Products

This application note describes the 4-20mA current loop — a common technique for transmitting sensor information in industrial process-monitoring applications. (Sensors measure physical parameters such as temperature, pressure, speed, and liquid flowrates.) Current-loop signals are relatively insensitive to noise, and their power can be derived from a remotely supplied voltage. This makes current loops particularly useful when the information must travel a long distance to a remote location.