| 摘要 |
PURPOSE:To suppress a nonlinear distortion to obtain an equivalent variable resistance circuit which can be operated with a low voltage, by connecting one terminals of two current mirror circuits and connecting them to a constant current circuit and connecting the other terminals to another current mirror circuit. CONSTITUTION:Pairs of transistors TRs Q11 and Q12, TRs Q13 and Q14, and TRs Q15 and Q16 constitute current mirror circuits respectively, and collector currents of individual TRs are equal and comes to I/2. When the emitter dynamic resistance is denoted as re and the current amplification factor of NPN TRs Q11-Q14 is denoted as betaN and that of PNP Ts Q15 and Q16 is denoted as betaP , an equivalent resistance R viewed from a point D in a figure is as indicated by a formula I , and the equivalent resistance is VT/I if the thermal voltage is denoted as VT and betaN and betaP are larger than 1. Thus, a nonlinear distortion is suppressed to obtain the equivalent variable resistance circuit which can be operated with a low voltage. |
