Instrumentation Amplifier : Derivation and Explaination(English)

Instrumentation amplifier Definition: Instrumentation amplifier is basically a high gain difference amplifier with high input impedance that amplifies the low level output signal from transducer by rejecting noise and interference in the signal. INTRODUCTION: Many industrial systems, process control systems and consumer systems require precise measurement of physical quantities like temperature , pressure, humidity, weight, etc. For example: Sugar factory : flow, level, temperature of juice Plastic furnace : Temperature Diary plant : Temperature and humidity Such physical quantities are converted into proportional electrical signal using transducer. The most of the transducer outputs are low level signals and not able to drive next stage of system Sometimes the transducer is placed far away from control room location and signal may be subjected to noise and atmospheric interference . Hence to amplify the low level signal and reject noise and interference, Instrumentation amplifier is used It is also called as Data amplifier Advantages of instrumentation amplifier: Precise adjustment of gain is possible by Rg Accurate adjustment of gain is possible by selecting low tolerance resistors Input impedance is very high Output impedance is very low Due high CMRR , it has capacity to reject common mode signals Applications of instrumentation amplifier: Temperature controller Temperature indicator Light intensity meter Analog weight scale