| 摘要 |
PURPOSE:To attenuate a large signal into a low distortion factor with a control circuit of a low current by connecting the 7th and 8th transistors (TRs) to the 5th and 6th TRs connected as a collector load of the 3d and 4th TRs connected differentially so as to apply feedback amplification. CONSTITUTION:A terminal C is a control terminal, and a voltage of the terminal controls the distribution ratio of the bias current 2I0 to NPN TRs Q3, Q4. the shared current is converted into a VBE by PNP TRs Q5, Q6 to control the base potential of the PNP TRs Q1, Q2. TRs Q7, Q8 added for feedback amplification are provided to the TRs Q5, Q6 and the TRs decreases the base current of the TRs Qdelta1, Q2 changed in proportion to the signal current to the effect of 1/hFE and returns it to the collector of the control TRs Q3, Q4. The TRs Q7, Q8 act like decreasing the distortion factor to 1/hFE.
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