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WHAT is the role of an instrumentation amplifier in strain gauge measurement system and WHY do we place the am? WHAT is the role of an instrumentation amplifier in strain gauge measurement system and WHY do we place the amplifier before the filter in the channel? jtr246 replied: "The signal from a strain gauge bridge will have a large common mode voltage, and any current drawn from the bridge will affect the result. The instrumentation amplifier will ground-reference and amplify the voltage difference at the strain gauge. It will also provide a low impedance output, which means that any filter will have a nice stable output to work on. In addition, some strain gauge circuits will have more than one signal that you have to connect to...which means that you will need a precision matched pair of filters, which is a tough thing to do." how can i design an instrumentation amplifier using INA122P? INA122P itself is an Instrumentation amplifier!! i know!! But this is the assignment given by our professor!! He has asked us to design instrumentation amplifier using INA122P for following specifications:
1.INPUT VOLTAGE - (O-10) millivolts
2.OUTPUT VOLTAGE- (0-5) VOLTS
please help!! give me a detailed idea on how to design it!! please help!! Ecko replied: "Get the data sheet first (link below).
Maybe you are supposed to work out an error budget. Thus take into account the common mode voltage, power supply rejection, linearity, noise (if you want to go that far), temperature drift, bias current errors, and the gain. It is just like an op- amp in those ways.
It is a differential amplifier with a high impedance input, whereas an op-amp (when configured as an amplifier) is not differential, or if configured as a differential amplifier, has low input resistance.
Instrumentation amplifiers usually have good input common mode rejection (at least 86dB in this case), as their purpose is often to extract (ground reference) a small signal of a few mV from a large common mode of several volts, like in a bridge circuit. They often have high configured gain (10,000 in this case), good DC performance. This amplifier could also be useful for extracting ECG and EEG signals from electrodes on the body.
The data sheet has application information. How to use it. The circuit is very simple, and the basic design is just to work out the gain resistor from the formula, and what power supply it needs, and where to put the ref pin. Note this is a single supply unit that can have its input 100mV below the supply rail. The rest is to work out the error budget." what is the difference between DIFFERENTIAL AMPLIFIER & INSTRUMENTATION AMPLIFIER? please answer above question in detail and with respect to op amp-741. ccc replied: "Refer "Op Amps & linear ICs" textbook by Ramakant Gayakwad.It explains this. Limited space available below to answer this Q."
Rob replied: "Hope the following web pages will be useful to you:
" IC no of cheep instrumentation amplifier? In my project we have to amplify the
0.1-2 mV input to 0.1-2V
for that we need instrumentation amplifier. As our input have +Vin and -Vin.
Will u please tell me some ic no (as cheep as possible).
Thank you.
Barath. Peter K replied: "Did you mean "cheap"?
Anything in the 741 family will be cheap."
dm300570 replied: "AD623 Cost about £3 (UK)
I have used this for thermocouple measurments and it works very well. Can use single +5V or dual ±5V supplies & it has rail to rail output" need some clarifications about connectin a wheatstone bridge to instrumentation amplifier AD620? i am usin a RTD to measure temperature.RTD is one arm of the bridge(Pt 1000)
other arms are precision resistors(1000ohms).
in clockwise order startin frm the top left arm it is R,RTD,R ,R
the input to the AD620 is from the mid points .The top points of the bridge is connected to the dc supply.
i want the Ad 620 to give a linear o/p in the range 0 to 5volts so that i can measure the temperature range 0 to 150 degrees
the major problem is i am not sure whether to use 2 different dc supplies for the bridge and AD620 or a single supply which wud b better?
i am also not sure where to connect the REFERENCE terminal of AD620
also tell me if the o/p of AD620 is measured w.r.t REF or its GND
infact i tried the circuit with a common dc supply and the REF connected to GND of AD620 but when the bridge was perfectly balanced there was all an o/p of 0.6volt.why?
please if possible give the complete circuit Bob M replied: "look at the app sheet for that device. AD has always been very good about app notes" |
| interesting sites |
Instrumentation amplifier - Wikipedia, the free encyclopedia Instrument amplifier - Wikipedia, the free encyclopedia Instrumentation amplifier: Definition from Answers.com The instrumentation amplifier : OPERATIONAL AMPLIFIERS Three is a Crowd for Instrumentation Amplifiers - Maxim Instrumentation Amplifiers | Amplifiers and Comparators | Analog Devices Instrumentation Amplifier Linear Technology - Instrumentation Amplifiers Instrumentation Amplifiers - Dual Supply - INA128 - TI.com Instrumentation Amplifiers - Single Supply - INA326 - TI.com |
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| instrumentation amplifier resistor, differential amplifier, instrumentation amplifier op-amps, instrumentation amplifier common-mode, instrumentation amplifier |
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