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    Lecture 10 Operational Amplifiers 2

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    Murali krishnan.M
    The document discusses various applications of operational amplifiers including comparators, voltage followers, signal modulation, mathematical operations, filters, and voltage to current conversion. It provides examples of op-amps being used as amplifiers, inverters, comparators for alarms, pulse width modulators for motor control, summation circuits, difference amplifiers, integrators, differentiators, and biopotential amplifiers for measuring weak electric signals from living organisms. Biopotential amplifiers require high input impedance, safety features, adjustable gain, and other characteristics to accurately measure and record small biomedical signals.

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    Lecture 10 Operational Amplifiers 2

    Uploaded by

    Murali krishnan.M
    19 views13 pages
    The document discusses various applications of operational amplifiers including comparators, voltage followers, signal modulation, mathematical operations, filters, and voltage to current conversion. It provides examples of op-amps being used as amplifiers, inverters, comparators for alarms, pulse width modulators for motor control, summation circuits, difference amplifiers, integrators, differentiators, and biopotential amplifiers for measuring weak electric signals from living organisms. Biopotential amplifiers require high input impedance, safety features, adjustable gain, and other characteristics to accurately measure and record small biomedical signals.

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    The document discusses various applications of operational amplifiers including comparators, voltage followers, signal modulation, mathematical operations, filters, and voltage to current conversion. It provides examples of op-amps being used as amplifiers, inverters, comparators for alarms, pulse width modulators for motor control, summation circuits, difference amplifiers, integrators, differentiators, and biopotential amplifiers for measuring weak electric signals from living organisms. Biopotential amplifiers require high input impedance, safety features, adjustable gain, and other characteristics to accurately measure and record small biomedical signals.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    19 views13 pages

    Lecture 10 Operational Amplifiers 2

    Uploaded by

    Murali krishnan.M
    The document discusses various applications of operational amplifiers including comparators, voltage followers, signal modulation, mathematical operations, filters, and voltage to current conversion. It provides examples of op-amps being used as amplifiers, inverters, comparators for alarms, pulse width modulators for motor control, summation circuits, difference amplifiers, integrators, differentiators, and biopotential amplifiers for measuring weak electric signals from living organisms. Biopotential amplifiers require high input impedance, safety features, adjustable gain, and other characteristics to accurately measure and record small biomedical signals.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 13

    Operational Amplifiers-2

    How are Op-Amps used?

    • Comparator
    • Voltage follower
    • Signal Modulation
    • Mathematical Operations
    • Filters
    • Voltage-Current signal conversion
    Non-inverting Op-Amp

    www.wikipedia.org

    Uses: Amplify…straight up
    Inverting Op-Amp

    www.wikipedia.org

    Uses: Analog inverter


    Comparator

    V1
    Vout
    V2

    www.allaboutcircuits.com

    Uses: Low-voltage alarms, night


    light controller
    Pulse Width Modulator
    • Output changes when
    – Vin ~= Vpot
    • Potentiometer used to vary
    duty cycle

    www.allaboutcircuits.com Uses: Motor controllers


    Summation

    www.wikipedia.org

    Uses: Add multiple sensors inputs until a


    threshold is reached.
    Difference

    V 2 R3  R1 R4 V1 R3
    Vout  
    ( R4  R2 ) R1 R1

    If all resistors are equal:

    Vout  V2  V1
    Integrating Op-Amp

    www.wikipedia.org

    Uses: PID Controller


    Differentiating Op-Amp

    www.wikipedia.org

    (where Vin and Vout are functions of time)


    Biopotential Amplifiers
    • Basic function
    – to increase the amplitude of a weak electric signal
    of biological origin
    – typically process voltages
    – In some cases processes current also
    Typical bio-amp requirements
    • high input impedance -greater than 10 MΩ.
    • safety: protect the organism being studied
    – careful design to prevent macro and microshocks
    – isolation and protection circuitry to limit the current
    through the electrode to safe level
    • output impedance of the amplifier
    – should be low to drive any external load with minimal
    distortion
    • gain greater than 1000
    – biopotentials are typically less than a mV.
    • most bio potential amplifiers are differential
     signals are recorded using a bipolar electrodes which are
    symmetrically located
    • high common mode rejection ratio
    • bio-potentials ride on a large offset signals
    • rapid calibration of the amplifier in laboratory
    conditions
    • adjustable gains
     often the change in scale is automatic
     therefore calibration of the equipment is very important

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