-90° phase shift circuit that can vary from 0 to -180°

The basic working principle is the same as cc12~12n, except that the polarity of the phase is changed
: here only the calculation method of the variable range of the phase is explained. f o-1kHz, Qu =
- 600 ~ - 120 0, Co = 0.01UF. , Pi. =15.92kQ, if R． Variable
, phase angle. ≯= - 2tan-'(Rx/R.), when Rx =R. When the house has 90 mouths,
    if you boast a; tan (庐/2), then the mother = one 6. At this time, the mouth = 0.577, and
the jealousy _1 plus. When, d; 1,73'2, therefore, the minimum value of chu Wangyun said mtⅡ is
2,174kQ (Rm.n≤Ro × mouth. Yue,, =9.l.7 kC2), and the maximum value of Gongqu is
27.55 kQ (U m. Wei≥month.×df】t.) = 27.sskQ)o If a 9.ik(h-
朐 resistor and two 20kokJ variable resistors are used to form Rx, the actual phase change range
is;