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  1. K

    opamp roll-off

    Do low frequency opamps have any advantage over high frequency opamps?
  2. K

    opamp roll-off

  3. K

    opamp roll-off

    I was thinking the loss was due to voltage loss at the base emitter junctions because of capacitance. And that the slew rate specification guarantees low signal distortion.
  4. K

    opamp roll-off

    Hero99, the post is about roll-off. A 20db/decade roll-off of an opamp approaches the limitation of the device. You extend the bandwidth of an opamp by reducing gain.
  5. K

    opamp roll-off

    A capcitor fe Hero99 said operating the 741 opamp on a 20db/decade curve is a good idea. I agree. It is only a general purpose device.
  6. K

    opamp roll-off

    A triangle wave? A sinewave becomes a triangle wave exceeding the slew rate? Any high frequency approaching the  slew rate is too high. Slew rate is a characteristic of the performance of the device. It's the same as device frequency limitation.
  7. K

    opamp roll-off

    I don't understand slew rate. It is a fuction of voltage and time. Better opamps have great slew rates.
  8. K

    opamp roll-off

    And that is why operating the opamp at 100Khz doesn't matter. The external capacitors dictate a 20db/decade roll off. But what if you don't have external capacitors. Operating the opamp beyond the bandwidth doesn't make more distortion?
  9. K

    IC's

    Many integrated cirucuits have either no resistors or a few low value ones. So how much do they offer to designs? And many IC's have a wide range of operation. Would a small IC, like a voltage regulator, use many different types of transisotrs?
  10. K

    3 x Inductance one core

    Inductors have a self resonant frequency because of the winding capacitance. I'm not sure why the self resonant frequency is avoided, but it may be because the winding capacitance is equal to a poorly constructed capacitor.
  11. K

    opamp roll-off

    Filter circuits attenuate the same as an opamp would above it's bandwidth. It's not recommended to allow the opamp to reach it's 40db/decade attenuation because it might oscillate. I'm wanting to know if the distortion is more appreciable above the opamps bandwidth with the attenuation at...
  12. K

    Amplification and loss

    Is loss in amplifiers any indication of design? Could you design a good amplifier with a lot of loss? A resistor causes loss, but no distortion. Many times I have had to reduce a signal after amplifying it. Is this a design problem?
  13. K

    bipolar transistors

    Most designs can't account for the linearity difference between bipolar transistors and MOSFETS. But very large designs suffer from linearity problems, component manufacturing, design etc.
  14. K

    opamp roll-off

    Is utilizing opamp roll-off a good idea? A 741 opamp has a gain of 100 at 100KHz, and the output is stable. External filtering components are most often used, so is opamp roll-off avoided? If I set the gain at 1000 and use a higher frequency to bring the gain to 500, would that be acceptable design?
  15. K

    3 x Inductance one core

    The problem with high current inductors is that their XL/R is always inherently low. So the frequency needs to be very high to get good resonant filtering. A series of three inductors would probably still be inadequate. A typical AC to DC power supply doesn't have resonance, and has better...
  16. K

    Electrolytic Capacitor

    There are non-polarized electrolytic type capacitors, and they are good when you need high capacitance without worrying about polarity. But I don't know if any products use them.
  17. K

    Parallel A/D converters

    Can you compare the output of two parallel A/D converters and produce a better conversion? A comparator at the output of both A/D converters could produce more accuracy. An example is a differential opamp where common mode noise is eliminated by two inputs.
  18. K

    3 stage battery charger question

    Voltage regulators are available for all voltage and current requirements. A typical high power battery charger might have a microcontroller and a voltage regulator. Efficiency is the main concern with high power battery chargers.
  19. K

    bipolar transistors

    Turn-on voltage .6V. All designs are depenedent on voltage and curent. Voltage is a real consideration. But you can use any value of voltage for a circuit.
  20. K

    Capacitors

    ESR is a rating. But a 1000uF capacitor is only good for low frequency.
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