Comments on: How to Derive the Instrumentation Amplifier Transfer Function https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/ Electronics Design and Modeling with Emphasis on Analog Design Thu, 30 Nov 2017 22:47:45 +0000 hourly 1 By: Adrian S. Nastase https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-41958 Thu, 30 Nov 2017 22:47:45 +0000 http://masteringelectronicsdesign.com/?p=621#comment-41958 In reply to john.

You can use INA126 (Texas Instruments). RG is the gain resistor. With RG = 162 ohms, 1% tolerance, the gain is 500.

]]> By: Hasrat Ali Anjum https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-41803 Sat, 25 Nov 2017 13:43:58 +0000 http://masteringelectronicsdesign.com/?p=621#comment-41803 In reply to Grant.

Ley us U3 non inverting terminal voltage Vp then
Vp=V11*R2/(R1+R2). {by voltage divider rule}
& Inverting terminal is connected R3 with V12 voltage
Now. R4=R2,R3=R1,
Apply superposition theorem
(1). Vp=0 then U3 act like a inverting amplifier
So Vout(1)’= –(R4/R3)V12,=–(R2/R1)V12,
(2) V12=0 then U3 act like a non-inverting amplifier so, Vout(1)”=Vp*(1+R4/R3)=(1+R2/R1)Vp
=(1+R2/R1)(R2/R1+R2)*V11
Vout(1)” = V11*(R2/R1)
Vout1=Vout(1)’+Vout(1)”
=R2/R1*(V11–V12)

]]> By: john https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-41750 Thu, 16 Nov 2017 14:38:43 +0000 http://masteringelectronicsdesign.com/?p=621#comment-41750 hello,how to design an intrumentations amplifers to satisfy a fixed differential voltage gain of Af=500? please reply me as soon as possible

]]> By: Tasnim Taleeb https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-41635 Fri, 27 Oct 2017 19:34:06 +0000 http://masteringelectronicsdesign.com/?p=621#comment-41635 Prove that the gain of the INA 126 amplifier is equal to ? ?
?? ????/??

]]> By: Adrian S. Nastase https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-35435 Thu, 19 May 2016 05:35:56 +0000 http://masteringelectronicsdesign.com/?p=621#comment-35435 In reply to Marwah.

I don’t understand this question. You need to reformulate it.

]]> By: Marwah https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-35048 Sun, 01 May 2016 08:47:43 +0000 http://masteringelectronicsdesign.com/?p=621#comment-35048 How to drive common mode gain of the first stage?

]]> By: Adrian S. Nastase https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-33601 Thu, 25 Feb 2016 06:27:01 +0000 http://masteringelectronicsdesign.com/?p=621#comment-33601 In reply to ashish burande.

I think my article shows that. You need to choose an instrumentation amplifier (go to digikey.com) and look in the data sheet for the transfer function. Should be similar with what I describe here. You need to calculate a resistor value to set the gain. 1 mV is a small signal. You need to choose a low noise amplifier with low offset.

]]> By: Adrian S. Nastase https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-33598 Thu, 25 Feb 2016 05:58:31 +0000 http://masteringelectronicsdesign.com/?p=621#comment-33598 In reply to Saif.

I would use 10kohm resistors.

]]> By: Saif https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-33411 Tue, 16 Feb 2016 22:04:58 +0000 http://masteringelectronicsdesign.com/?p=621#comment-33411 In reply to Adrian S. Nastase.

I use 200kohm for every resistors. Is the value make sense ?

I am now in the process of designing signal conditioning circuit for thermistor.
The temperature range is between 0-100 deg C.
So I make the maximum temperature which is 100 deg C as maximum output voltage which is 5V.

The value for V1 measured is 131.35mV
the value for V2 measured is 27.41mV

Then I calculate using your equation by substitute the Vo as 5V
and I find the value of RG is about 8491ohm.

Is my calculation is correct or not ?

]]> By: Saif https://masteringelectronicsdesign.com/how-to-derive-the-instrumentation-amplifier-transfer-function/#comment-33387 Tue, 16 Feb 2016 00:43:48 +0000 http://masteringelectronicsdesign.com/?p=621#comment-33387 Hello.
Very helpful articles.
Im in the process of design my signal conditioning circuit for thermistor. I do need this amplifier since the output from Wheatstone Bridge is in mV.
Is it make sense the resistor I used for this amplifier is all 200k ohm ?
Is it too big ?

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