High Quality Content by WIKIPEDIA articles! For a variety of reasons, in low-voltage electronics, voltage is a more frequently used data carrier. Thus electronic devices tend to be labeled with voltage inputs and outputs. However some devices are labeled in terms of current-input and -output (for example, a bipolar transistor). In such cases, a component is needed to convert (change) the electric attributes into a relay of information.A voltage-to-current converter changes the electric attribute carrying information from voltage to current. It acts as a linear circuit with transfer ratio k = IOUT/VIN [mA/V] having dimension of conductivity. That is why the active version of the circuit is referred also as a transconductance amplifier.