Key Facts from Reading Chapter 1

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The following facts are not profound and are possibly very obvious. Nonetheless, they might help cement certain concepts. Please add things you think would be helpful.

Transistors

MOSFET diagram <ref> University of Cambridge </ref>
  • Conduction in n-type material is from free electrons.
  • Conduction in p-type material is from holes (positive particles).
  • The function of metal-oxide-semiconductor field-effect transistors (MOSFETs) depends on the voltage applied to the gate.
    • Certain ranges of voltage allow no current to flow between the drain and the source. In this way, the MOSFET acts like an open switch.
    • Another particular range of voltage allows current to easily flow from the source to the drain.
    • When the voltage is in between the ranges of open and closed switch, the MOSFET can smoothly control the amount of current flowing.
  • Bipolar Junction Transistors (BJTs) can act as either switches or current controls as well.

Amplifiers

  • An inverting amplifier has a negative voltage gain, .
  • A noninverting amplifier has a positive voltage gain, . (If you get this, you deserve a cookie)
  • The power gain,, is the ration of the output power to the input power
      • is the amplifier's input resistance and is the amplifier's output resistance.

Decibel Conversion

  • Power gain, , can be converted to decibels:

  • By the equation above, we can say voltage gain in decibels can be found with this equation: , where is the voltage gain and is the voltage gain is decibels.
  • Similarly, we can say current gain in decibels can be found with this equation: , where is the current gain and is the current gain is decibels.

Differential Amplifiers

  • Differential Amplifiers have two inputs. The terminal marked with a "+" is the noninverting input, and the terminal marked with a "-" is the inverting input.
  • The differential input signal is given by
  • The output of an ideal differential amplifier is given by .
  • The common-mode input signal is given by the following: .
  • A real differential amplifier's output is given by , where is the common-mode signal gain.

References

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Contributors

Christopher Garrison Lau I

Readers

Shepherd,Victor