Voltage-to-current converter

[swapna]

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).

http://electronicstopics.blogspot.com/2008/10/voltage-to-current-conv...