Useful Operational Amplifier Formulas and Configurations

August 23rd, 2009 by Adrian S. Nastase


My friends advised me that it would be helpful to have on this site the most common operational amplifier configurations and transfer functions or formulas.  So, here they are.  This article is not just a simple collection of circuits and formulas.  It also has links to the transfer function proof for these circuits so I hope it will be very helpful.  Make sure you post a comment and let me know how I can improve this page.  This article will be updated, so do check it often.

Non-inverting Amplifier

non-inverting-amplifier-1

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Note:  The proof of this transfer function can be found here:  How to Derive the Non-Inverting Amplifier Transfer Function.

Voltage Follower

voltage-follower-2

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Note:  This configuration can be considered a subset of the Non-inverting Amplifier.  When Rf2 is zero and Rf1 is infinity, the Non-inverting Amplifier becomes a voltage follower.  When a resistor has an infinity value, in practice it means it is disconnected.

Inverting Amplifier

inverting-amplifier-3image0062

Note:  The proof of this transfer function can be found here:  How to Derive the Inverting Amplifier Transfer Function

Differential Amplifier

differential-amplifier-4

image0082

Note:  The proof of this transfer function can be found here:  How to Derive the Differential Amplifier Transfer Function.

Non-inverting Summing amplifier

non-inverting-summing-amplifier-5

image0102

Note:  The proof of this transfer function can be found here:  How to Derive the Summing Amplifier Transfer Function.

Non-inverting Summing Amplifier with N Inputs

non-inverting-summing-amplifier-n-inputs-6

image0121

where n is the number of inputs.

Note:  The proof of this transfer function can be found here:  The Transfer Function of the Summing Amplifier with N Input Signals.

Inverting Summing Amplifier

inverting-summing-amplifier-7

image0141

Note:  The proof of this transfer function can be found here:  How to Derive the Transfer Function of the Inverting Summing Amplifier.

Inverting Summing Amplifier with N Inputs

inverting-summing-amplifier-n-inputs-8

image0161

where n is the number of inputs.

Note:  The proof of this transfer function can be found here:  How to Derive the Transfer Function of the Inverting Summing Amplifier.

Instrumentation Amplifier

instrumentation_amplifier_9

image018

Note:  The proof of this transfer function can be found here:  How to Derive the Instrumentation Amplifier Transfer Function.

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Are there any other Op Amp configurations you would like to see listed here?  Let me know.

Related Articles

  1. The Transfer Function of the Non-Inverting Summing Amplifier with “N” Input Signals In a previous article, How to Derive the Summing Amplifier Transfer Function, I deduced the formula for the non-inverting summing...
  2. Converting a Differential Amplifier into a Summing Amplifier Is there any link between a differential amplifier and a summing amplifier? Yes, it is. They can be easily converted...
  3. How to Derive the Summing Amplifier Transfer Function The summing amplifier, or the non-inverting summing amplifier, is an analog processing circuit with the transfer function (the summing amplifier...

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Categories: Analog Design, Operational Amplifier Formulas

2 Comments to “Useful Operational Amplifier Formulas and Configurations”

  1. Roberto says:

    cool blog

  2. dilandinga says:

    I bookmarked this link. Thank you for such a good job!

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