AMP01 instrumentation amplifier

Hi

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

  • 0
    •  Analog Employees 
    on Dec 12, 2014 9:42 PM

    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.

    Regards.

  • 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

    Regards

  • 0
    •  Analog Employees 
    on Jan 6, 2015 10:14 PM

    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.

    Regards,

    Jino