Twin-t-notch-filter

  
This filter is used to reject or block a frequency or band of frequencies. These filters are often designed into audio and instrumentation systems to eliminate a single frequency, such as 60Hz. Commercial grade components with 5%-10% tolerance produce a null depth of at least 30 to 40 dB. When a twinT network is combined with a TL081 op amp in a circuit, an active filter can be implemented. The added resistor capacitor network, R2 and C2, work effectively in parallel with the original twin-T network, on the input of the filter.
Twin-t-notch-filter - schematic

These networks set the Q of the filter. The op amp is basically connected as a unity-gain voltage follower. For a 60-Hz notch filter with a Q of 5, it is usually best to pick the C1 capacitor value and calculate the resistor Rl. Let C1 ~ 0.22 JlF. Then: R 1 ~ 12 KO - R 2 ~ 120 KO - C2 ~ 0.047 JlF Standard 5% resistors and 10% capacitors produce a notch depth of about 40 dB, as shown in the frequency response curve.



 

Recommended videos


  • Bandstop Filters
    Duration: 14:44.
  • low cut - high pass active R-C audio filter (schematic)
    Duration: 5:52.
  • Opamp
     

News


  • Physics
    Phononic crystals are arrays of rods or spheres that use interference effects to manipulate viational waves for purposes such as , ultrasound imaging, or sound proofing. Now researchers provide a visualization of a computer simulation
     31 March 2017
  • Hackaday
    If you've been enjoying [Elliot Williams'] posts about filters, you'll see there is a lot of difference between active and passive RF filters, although some of the ideas are the same. Watching the effect different circuit tweaks have in
     31 March 2017
  • Tom's Guide
    Tom's Guide Paired with the app, these earphones offer a form of augmented hearing that essentially layers ambient sound over whatever you happened to be listening to at the moment, creating a merged experience. Want a more secluded listenin
     4 March 2017
  • The Verge
    The Verge The thing to know with the way Here One uses this technology is that, right now, what you can do with and the "Live Remix" — an equalizer in the app that lets you raise or lower specific frequencies of the world around you &
     21 February 2017
  • Neowin
    Neowin myFFmpeg is a graphical front-end for FFmpeg, a command-line tool used to convert multimedia files between formats. The command line instructions can be very hard to master/understand, so myFFmpeg does all the hard work for you. This a
     13 February 2017
  • TWCN Tech News (blog)
    TWCN Tech News (blog) converter software fre:ac isn't a look but better than mostYes, fre:ac does support the addition of various before converting. We did not use this feature, so we're unable to say for sure how well it works, if at a
     12 December 2016
  • InfoQ.com
    Liary Howler.js Has 2.0 Release to Make Some Noise about... Released Simpson describes howler.js as a "modular liary" saying that it allows for "a lean core that can be extended to add more advanced functionality, such as the wealth of tool
     26 July 2016
  • GearNuke
    Uncharted 4 has some unlockable render modes including a cel-shared filter and various . These can be unlocked by using points that are acquired by finding the collectibles in the game. The following render modes and can be ...
     14 May 2016
  • Wired
    Wired More importantly, Smule has ported its technology to enhance an often missing feature in other video sharing apps. While apps like Viddy allow you to add background music to a video, Strum provides as well. Each of the 21 filters
     13 December 2012

.