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AMP01 instrumentation amplifier


Can anyone tel what is function of RC in the above figure.

  • Hi Vijay,

    AMP01 gain is 20 Rs/Rg, so at low frequencies the capacitor  will look like an open circuit thus giving you a gain of 20. While at high frequencies it will be short circuit and that gives you a gain of ~500. The RC circuit will provide some rejection of dc offsets and low frequency noise for an ac measurement.

    By the way, may I know your application? Thanks.


  • Thank you Jinol.

    For the above circuit although ratio of Rs and Rg is same for different combination of Rs and Rg the passband cut-off frequency varies.For ex Rs=100k and Rg=100k and other combination Rs=10k and Rg=10k although ratio is same passband cut-off frequency is different.Can any one tell a relation bet resistor values and cutoff frequency.

    Thank you


  • Hi Vijay,

    Sorry for the delayed response. Let's say for example we have a simple passive RC bandpass filter, the cutoff frequency is dependent on the values of the capacitor and the resistor. The cutoff frequency of the filter follows the formula:


    fcutoff = 1/(2*pi*R*C)


    You can try this tutorial (analog filters) for more information on filter design. Also, you can visit FILTER WIZARD | Analog Devices to help you on your future filter designs.