After a long experience of teaching in Instrumentation Engineeringover the period of time MADE EASY team realised that there is a need of good Handbook which can provide the crux of Instrumentation Engineering in a concise form to the student to brush up the formulae and important concepts required for GATE and other competitive examinations. This handbook contains all the formulae and important theoretical aspects of Instrumentation Engineering. It provides much needed revision aid and study guidance before examinations.