Monday, October 26, 2020

Important Formula of Transistor Tuned Amplifiers

( 1 ) Parallel resonance frequency

        fr = ( 1 / 2π ) √ ( 1 / LC – R2 / L2 )

( 2 ) Dynamic Impedance of parallel resonance circuit

        Z = L / CR

( 3 ) Q factor of parallel resonance circuit

       Q = XL / R

          = ωL / R

          = Energy Stored / Energy Lost

          = Reactive Power / Resistive Power

( 4 ) Voltage gain of tuned amplifier

       Voltage gain = βZC / Zin

       Where β = Current gain of the transistor

               ZC = Effective collector load

              Zin = Input impedance of amplifier

( 5 ) Relation between bandwidth and Q factor

       Q = fr / BW

      Where

          fr = Resonance frequency

             = 1 /  [ 2π √ ( LC ) ]

( 6 ) Bandwidth of double tuned circuit

       BWdt = kfr

      Where k = Coefficient of coupling

                dt = It is used for double tuned circuit

( 7 ) Critical coupling in the double tuned circuit

        Kcritical = 1 / √ ( Q1 × Q2 )

       Where

       Q1 = Quality factor for primary resonant circuit

       Q2 = Quality factor for secondary resonant circuit

( 8 ) The power losses in the tuned Class C amplifier is very small in high Q resonant circuit.

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Transistor Tuned Amplifier MCQs – 1

Transistor Tuned Amplifier MCQs – 2

Transistor Tuned Amplifier MCQs – 3

Transistor Tuned Amplifier MCQs – 4

Transistor Tuned Amplifier MCQs – 5

 


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