» Explanation of 'Transmitters'

Transmitters

A transmitter is an electronic device which propagates an electromagnetic signal.  In certain applications signals can also be transmitted using an analog 0/4-20 mA current loop or voltage based signal.

In industrial process control, a "transmitter" is any device which converts measurements from a sensor into a signal to be received, usually sent via wires, by some display or control device located a distance away. Typically in process control applications the "transmitter" will output an analog 4-20 mA current loop or digital protocol to represent a measured variable within a range. For example, a pressure transmitter might use 4 mA as a representation for 50 psig of pressure and 20 mA as 1000 psig of pressure and any value in between proportionately ranged between 50 and 1000 psig. (A 0-4 mA signal indicates a system error.) Older technology transmitters used pneumatic pressure typically ranged between 3 to 15 psig (20 to 100 kPa) to represent a process variable.

Generally and in communication and information processing, a transmitter is any object (source) which sends information to an observer (receiver). When used in this more general sense, vocal cords may also be considered an example of a "transmitter".