B.2 Übungsaufgaben zu Schwingkreise

Lösung zur
Aufgabe 8.7.1
(Tiefpass)

Widerstand

R   =   --1----
        2πfgC
                   1
    =   ------3------------−6--=  1,59k-Ω-             (B.2.1)
        2π ⋅ 10 Hz ⋅ 0,1 ⋅ 10 F

Lösung zur
Aufgabe 8.7.2
(Hochpass)

Kapazitätswert

C   =   --1----
        2πfgR
                 1
    =   --------------------= 132,6nF--              (B.2.2)
        2π ⋅ 1200Hz ⋅ 1000 Ω
Betragsverhältnis
U2-      ------1--------
U    =   ∘ -------1-----
  1        1 + (2πf1CR)2
         --------------1---------------
     =   ∘ ---------------1------------
           1 + (2π⋅500Hz⋅132,6⋅10−9F⋅1000Ω)2
     =   0,385--                                      (B.2.3)
         ------

Lösung zur
Aufgabe 8.7.3
(Schwingkreis)

Kapazität

C   =   ----1----
        (2πfr)2L
                 1
    =   -----4----2---------= 25,33nF--              (B.2.4)
        (2π10 Hz  ) ⋅ 0,01H
Widerstand
                   ∘ ---
R   =   bXk--=  b- ⋅  L-
        fr     fr ---C----------
        103Hz   ∘    0,01H
    =   --4----⋅  ---------−9-- = 62,83Ω-             (B.2.5)
        10 Hz     25,33 ⋅ 10 F    -------

Lösung zur
Aufgabe 8.7.4
(Schwingkreis)

Widerstand

R = Z1 =  12,5Ω-
          ------
(B.2.6)

Induktivität

       ∘ ---------
         Z2 − R2
L  =   ----2---2-
        ω2 −  ω1
       ∘ -----ω2-----------
         (25Ω )2 − (12,5Ω )2
   =   ------−1---(500s−1)2--=  40,59mH---             (B.2.7)
        300s   −   300s−1
Kapazität
     --1-    ---------1-----------
C  = ω21L =  (500s−1)2 ⋅ 0,04059H  = 98,55μF--
(B.2.8)

Lösung zur
Aufgabe 8.7.5
(Schwingkreis)

Widerstand

          -1-
R = Z1 =  Y1 =  25,0Ω--
(B.2.9)

Kapazität

        ∘ --2------
        --Y2-−-G2--
C   =          ω21
        ∘ω2-−--ω2-------------
          (0,08S )2 − (0,04S )2
    =   ---------------−1-2-- = 129,9μF              (B.2.10)
          300s− 1 − (503000ss−)1--    ---------
Induktivität
      1                 1
L =  -2---=  -----−1-2----------−-6--=  30,79mH----
     ω1C     (500s   ) ⋅ 129,9 ⋅ 10 F    ----------
(B.2.11)

Lösung zur
Aufgabe 8.7.6
(Schwingkreis)

Resonanzfrequenz

          ∘-R1-+--R2----
ω = ωr =    R2LC  − L2
          ---2----------
(B.2.12)

Lösung zur
Aufgabe 8.7.7
(Schwingkreis)

Resonanzfrequenz

         ┌ ------------
         ││     2   L-
ω = ω  = ∘  --R1-−-C----
      r     LCR22 − L2
         --------------
(B.2.13)

Lösung zur
Aufgabe 8.7.8
(Schwingkreis)

  1. Resonanzfrequenz
                        1
f = fr  =   ---∘------------2
            2π  LC  − (RC  )
                                   1
        =   ---∘-------------------------------------------
            2π  0,01H  ⋅ 100 ⋅ 10− 9F − (100Ω ⋅ 100 ⋅ 10−9F )2
        =   5,31kHz                                           (B.2.14)
            ---------
  2. Gesamtwiderstand
    Z    =   1--=  ---1---
-r       Yr    Re{Y-}
                         ( 1 )2
         R2-+-X2C-       -ωC---        ---1----
     =      R     = R  +   R    = R  + R (ωC )2

     =  100 Ω + -----------------1----------------
                100 Ω ⋅ (2π ⋅ 5310Hz ⋅ 100 ⋅ 10− 9F)2
     =  998,0Ω                                            (B.2.15)
        -------

Lösung zur
Aufgabe 8.7.9
(Schwingkreis)

  1. Frequenz
               1                  1
f1  =   --√------=  --√--------------−6--
        2π  L2C     2π  0,2H ⋅ 10 ⋅ 10 F
    =  112,5Hz--                                     (B.2.16)
  2. Frequenz
              ┌│ ----L--
       -1-│∘ 1-+-L12-
f2 =   2π    CL1
          ┌│ ------------------
        1 │∘      1 + 0,1H-
   =   ---  ------−-60,2H-----
       2π   10 ⋅ 10  F ⋅ 0,1H
   =   194,9Hz--                               (B.2.17)

Lösung zur
Aufgabe 8.7.10
(Schwingkreis)

Kapazität

          1                1
C   =   -2--- = --------------2--------
        ω1L1    (2π ⋅ 4000Hz ) ⋅ 0,01H
    =   158,3nF--                                   (B.2.18)
Induktivität
L2   =  --1--−  L1
        ω22C
                      1
     =  --------------2-----------−9- − 0,01H
        (2π ⋅ 3000Hz ) ⋅ 158,3 ⋅ 10 F
     =  7,78mH--                                        (B.2.19)