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5th-7th-9th up to 200 MHz
[ Up ] [ 3rd Overtone Oscillator Circuit ] [ 5th overtone ] [ 5th-7th-9th -- 200 MHz ]
R1 10K
R2 4.7K
R3 470 Ohm
R4 560 Ohm
TR1 BF180 or similar
C1 C2, C3, C4, See Below
C5 0.001mF
L1 wound is on a 7.62 diameter former with Neosid F29 core
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75 MHz
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120 MHz
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150 MHz
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200 MHz
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C1 (pF)
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8.00
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8.00
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5.00
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3.00
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C2 (pF)
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100.00
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50.00
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25.00
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20.00
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Ic (mA)
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25.00
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25.00
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5.00
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5.00
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RE (Ohms)
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510.00
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390.00
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1.1 k
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1.1 k
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RL (Ohms)
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470.00
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300.00
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600.00
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600.00
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Lp (mH)
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0.25
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0.10
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0.08
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0.05
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The above diagram shows a true series resonant oscillator circuit suitable for use up to 200 MHz
It is recommended that transistors for use in this circuit have a high DC gain (HFE) and a low base resistance (RBB). Also ensure that the transit frequency is at least ten times that of the oscillator frequency.
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