Pages

Saturday, 17 March 2012

BAND-STOP FILTERS

Band-stop filters are also called band-elimination, band-reject, or notch filters; this kind of filter passes all frequencies above and below a particular range set by the component values. This type of filters can be made out of a low-pass and a high-pass filter, just like the band-pass design, except that the two filter sections are connected in parallel with each other instead of in series.

The low-pass filter section is comprised of R1, R2, and C1 in a “T” configuration. The high pass filter section is comprised of C2, C3, and R3 in a “T” configuration as well. Together, this arrangement is commonly known as a “Twin-T” filter, giving sharp response when the component values are chosen in the following ratios:

Component value ratios for the "Twin-T" band-stop filter

R1 = R2 = 2(R3)

C2 = C3 = (0.5) C1

The frequency of maximum rejection (the “notch frequency”) can be calculated as follows:

fnotch =1/4*3.14*R3C3

1 comment:

  1. Thank you for sharing detailed information about band stop filter. Just a few months ago, I was in desperate need of a band stop filter. Following an online search, I came upon the Anatech electronics website. I received all of my required band stop filter, as well as requested for a custom band stop filter, I have received products on time from them. You can also reach out to them if you require any band stop filters.

    ReplyDelete