Instrumentation Viva Questions

  1. What are the Types of Op-Amps ?

    Broadly its categorized as BJT based op-amp, FET(JFET and MOSFET) based op-amps. Except this these are also categorized according to frequency range, power consumption and operating voltage range.

  2. Explain about ChemFET, ISFET and ENFET.

    View Wikipedia pages.

  3. What are the other types of FET ?

    HEMT, MESFET, MODFET, NOMFET, OFET, DEPFET, CNTFET, … see the page on FET on Wikipedia.

  4. What is IGBT ?

    Insulated Gate Bipolar Transistor.  It is a device for power control. It has a structure akin to a MOSFET coupled with a bipolar-like main conduction channel. These are commonly used for the 200-3000 V drain-to-source voltage range of operation. Power MOSFETs are still the device of choice for drain-to-source voltages of 1 to 200 V.

  5. Name of FET and CMOS Op-amps ?

    TL084, National Semiconductor LF series, LT1056,.


    LMCXXXX —-National


    ICLXXXX —–Intersil

    LTCXXX ——Linear Technology

    TLCXXX ——-Texas Instruments

    S/H IC names ?



  6. What is Charge Pump?
  7. What is Loseless resistor/ Switched capacitor ?
  8. What is low side and high side switching ?
  9. What is retriggerable monostable vibrator ?
  10. what is a gimmick capacitor ?