Difference and Instrumentation Amplifier

[kahei]

What is the use of Difference and Instrumentation Amplifier?

[waht]

Instrumentation amp is like a differential amp but is made more precise, and as a result it's used it precision equipment, and test equipment such as quality multimeters.

[dlgoff]

Just to add a bit...
An instrumentation (or instrumentational) amplifier is a type of differential amplifier that has been outfitted with input buffers, which eliminate the need for input impedance matching and thus make the amplifier particularly suitable for use in measurement and test equipment.Instrumentation Amplifier (http://en.wikipedia.org/wiki/Instrumentation_amplifier)