Instrumentation Amplifier with Electronic Gain Control

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  • เผยแพร่เมื่อ 16 พ.ย. 2024

ความคิดเห็น • 18

  • @STEMprof
    @STEMprof  11 หลายเดือนก่อน

    Thanks for watching. For more Op Amp Circuit examples please see the list below. Note that MOSFET Transistor and Op Amp part numbers mentioned in video are only for illustration purposes and does NOT mean that they are proper choices for the specific reference voltage Vref value in this video. Depending on the chosen FET transistor, Vref needs to be adjusted to make sure transistor remains in deep ohmic region (so Vref might be required to be as low as ~0.5 volt). And for additional circuit examples see:
    Op Amp Amplifier with Electronic Gain Control th-cam.com/video/NoNgQpbj77Y/w-d-xo.html
    VCA Electronic Gain Control (Part 1): Voltage-Controlled Attenuator Overview th-cam.com/video/cFzYZsPEtP0/w-d-xo.html
    Switched-Capacitor Amplifier Design: How does it work? th-cam.com/video/n8UOTmPI4aI/w-d-xo.html
    Op Amp Analog Computer Differential Equation Solver th-cam.com/video/ENq39EesfPw/w-d-xo.html
    Thermometer Circuit Design with Op Amp & BJT transistor th-cam.com/video/55YsraFE0rg/w-d-xo.html
    Push-Pull Power Amplifier with Darlington Transistors th-cam.com/video/866MYibo8yE/w-d-xo.html
    Analog Logarithm Computer th-cam.com/video/RpKEq5WyoLg/w-d-xo.html
    Lowpass Butterworth Filter: th-cam.com/video/UzCjkwqy-9w/w-d-xo.html
    Analog Computer to Raise Signal to power n th-cam.com/video/IUTlBH1UraE/w-d-xo.html
    Triangle Oscillator Op Amp circuit th-cam.com/video/JF5Up_cuL9k/w-d-xo.html
    Differential Equation Solver Analog Circuit th-cam.com/video/R3X5AYNZGEI/w-d-xo.html
    Complex Sinusoid Oscillator th-cam.com/video/GXRhmwmS5Zk/w-d-xo.html
    Sawtooth Waveform Generator design with OpAmp, JFET, BJT th-cam.com/video/5zHXTx-Vl20/w-d-xo.html
    op amps Circuit with feedback loops to design an analog computer that solves a second order differential equation th-cam.com/video/HeZRtnRXpEI/w-d-xo.html
    For more analog circuits and signal processing examples see: th-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html
    I hope these Circuit design and analysis videos are interesting. 🙋‍♂

  • @randyscorner9434
    @randyscorner9434 11 หลายเดือนก่อน +1

    Definitely brings back college circuit courses, and with additional experience it makes so much more sense. I immediately thought of this as a gain control for an audio preamp. I increasingly find the need to control preamp gains remotely and have found it difficult to do without injecting noise. As we network audio systems they become more distributed and gain controls are no longer practical to have at the location of the microphone input. Being able to adjust them remotely for system gain stage balance makes more sense, even though most manufacturers are not yet doing it. This is an excellent example of one way to do it. Thanks for the thorough derivation.

    • @STEMprof
      @STEMprof  11 หลายเดือนก่อน

      Thank you for watching and sharing your insights. Glad that this Instrumentation Amplifier Example is useful. For more examples please see th-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html
      As you mentioned, Remote or Automatic Gain Control (AGC) are among the applications of this circuit. We can use this peak/RMS detector circuit th-cam.com/video/4aG5NYX8tGo/w-d-xo.html and then compare its output with your desired peak/RMS level and then adjust the gain accordingly.
      Thanks again for watching and your interest. 🙏🙋‍♂️

  • @iholland
    @iholland 10 หลายเดือนก่อน +1

    Hi. I've spent the afternoon watching a lot of your videos. Great stuff! Thanks. A minor issue with this one - I believe your very last expression for Vo is actually Av, since V2-V1 is absent.

    • @STEMprof
      @STEMprof  10 หลายเดือนก่อน

      Thank you for watching, your interest, detailed attention and your follow-up comment. I am glad that you like my videos. You are right, in that very last example equation around minute 34:30 I inadvertently dropped the (V2-V1) in the denominator while present the specific Av value assuming Rf=100kOhm. Thank you. For more examples please see: Op Amp Amplifier with Electronic Gain Control th-cam.com/video/NoNgQpbj77Y/w-d-xo.html
      Analog Logarithm Computer th-cam.com/video/RpKEq5WyoLg/w-d-xo.html
      Power Amplifier Design with Transformer th-cam.com/video/gKlJrqGqeCI/w-d-xo.html
      Op Amp Analog Computer Differential Equation Solver th-cam.com/video/ENq39EesfPw/w-d-xo.html
      Instrumentation Amplifier with Electronic Gain Control th-cam.com/video/C4tghZ-q6Zs/w-d-xo.html
      Push-Pull Power Amplifier with Darlington Transistors th-cam.com/video/866MYibo8yE/w-d-xo.html
      Thermometer Circuit Design with Op Amp & BJT transistor th-cam.com/video/55YsraFE0rg/w-d-xo.html
      I hope you also enjoy these further examples. Thanks again 🙏

  • @martinmartinmartin2996
    @martinmartinmartin2996 10 หลายเดือนก่อน +1

    Some mention of the distortion that may be created by the NMOS gaine control would be VERY valuable.

    • @STEMprof
      @STEMprof  10 หลายเดือนก่อน

      Thanks for watching, sharing your thoughts and suggestions. You have a good point. I had a lot to cover in this detailed long video and packing more topics was concerning. A related example is th-cam.com/video/NoNgQpbj77Y/w-d-xo.html . I will post more Amplifier examples in my Circuit Design/Analysis repository th-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html . Thanks Again 🙏

  • @STEMprof
    @STEMprof  7 หลายเดือนก่อน

    To see more electronic amplifier videos:
    1x, 10x, 100x, 1000x Switched-Gain Instrumentation Amplifier th-cam.com/video/9-MLqyewXW8/w-d-xo.html
    Variable Gain Instrumentation Amplifier for designing Thermometer Current Source th-cam.com/video/Ggf0yCaTTiY/w-d-xo.html
    Instrumentation Amplifier Explained th-cam.com/video/Yq767et8BbY/w-d-xo.html
    Gain & CMRR of Instrumentation Amplifier Explained th-cam.com/video/Bw29QjHHzGo/w-d-xo.html
    Instrumentation Amplifier design with Differential Instrumentation Amplifier with BJT transistor th-cam.com/video/2xJpqfexsPg/w-d-xo.html
    I hope these videos are helpful

  • @frunsebischkek1050
    @frunsebischkek1050 10 หลายเดือนก่อน +1

    Thank you. I like your way explaining analog electronics very much. 👍
    Is it always the case that MOSFETs or other electronical parts, which are siting on the same silicon chip, are matched?

    • @STEMprof
      @STEMprof  10 หลายเดือนก่อน +1

      Thanks for watching and your comment. Glad that you like my videos and they are useful. Answering your good question: Not necessarily, there are many forms of mismatch between electronic components. The severity of mismatch depends on the component, package and design. Having component on the same substrate in the same package helps with reducing the mismatches hopefully to a level that is acceptable for a given desired application. For more circuit examples involving matching transistors please see:
      Wilson Current Mirror and Current Source Design Tutorial th-cam.com/video/LfbfJYrovN0/w-d-xo.html
      Thermometer Circuit Design with Op Amp and BJT transistor th-cam.com/video/55YsraFE0rg/w-d-xo.html
      Op Amp Amplifier with Electronic Gain Control th-cam.com/video/NoNgQpbj77Y/w-d-xo.html
      Anti-Log Analog Computer with Temperature Compensation th-cam.com/video/kk2c7Gk3nW4/w-d-xo.html
      I hope this explanation and these circuit examples are helpful and interesting.

  • @666aron
    @666aron 11 หลายเดือนก่อน +1

    Thank you for this fantastic, in-depth video.
    When I saw this, I immediately thought of an audio compressor circuit. We could get the peak of the input signal using an ideal diode circuit in full-wave rectification. Now, the only problem is that this circuit amplifies the signal. If I wanted a damper, I would need to have an inverting second stage, with the FET as an input element.
    What is your opinion? Should I use a single FET with a biased signal or two FETs in a push-pull configuration with both gates driven by your first stage? Also, crossover distortion will be problematic if I'm not biasing the input sound.

    • @STEMprof
      @STEMprof  11 หลายเดือนก่อน +1

      You're welcome. Thanks for watching and your follow-up comment. Glad that you like Instrumentation Amplifier Video. As you mentioned, Automatic Gain Control (AGC) is one of the applications of this circuit. We can use this peak/RMS detector circuit th-cam.com/video/4aG5NYX8tGo/w-d-xo.html and then compare its output with your desired peak/RMS and then adjust the gain accordingly. While there are many methods to implement full-scale AGC circuit (much more capable than this core concept example), my suggestion is a quick scrappy work-around here (to achieve your design) by adding an additional attenuating stage at the output that by default is attenuating to lowest level that you might need. Then the matched-FET gain stage just works as a gain controlled stage that counteracts the default attenuation as much as needed to get the signal to the right level. For more circuit examples please see my Analog playlist th-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html
      I hope this is helpful. 🙂

    • @666aron
      @666aron 11 หลายเดือนก่อน +1

      @@STEMprof Thank you again for this extensive reply. It was really helpful. This approach sounds more optimal with respect to semiconductor count, so I'll start the design this way.

    • @STEMprof
      @STEMprof  11 หลายเดือนก่อน

      You are very welcome. Thanks again for watching and your interest. Best wishes with your circuit experiment. 👍🙋‍♂️

  • @biswajit681
    @biswajit681 11 หลายเดือนก่อน +2

    Could you please also mention where is this circuit is being used in the practical circuit/ World......your videos are very good but why are we studying particular circuit that should be clear....

    • @STEMprof
      @STEMprof  11 หลายเดือนก่อน +1

      Thanks for watching and your comment. Glad that these circuit videos are useful. As mentioned in video, precision gain-controlled amplifier for instance for optical sensor is one application especially when Automatic Gain Control (AGC) is desired that requires Electronic gain adjustment. For more circuit examples please see my Analog playlist th-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html
      I hope they are interesting and useful. Thanks again. 🙏

    • @qemmm11
      @qemmm11 10 หลายเดือนก่อน +1

      It can be used in the practical circuit (world)😊

    • @STEMprof
      @STEMprof  10 หลายเดือนก่อน

      @@qemmm11 Thanks for watching 🙋‍♂️