A block diagram of an automatic instrument for measuring nonelectrical quantities, com- prising primary transducer PT, bridge circuit BC, amplifier A, motor M, and kinematic trans- mission KT, is shown in Fig. I.
М. А. Ураксеев, N. I. Prazdnikov, Zeng Sh · 1977
In the bridge circuit (Fig. 2), in certain cases, the arms consist of inductive transducers with regulated inductance [4-7]. In this case the moving parts of each pair of transducers connected in opposite arms of the bridge, are rigidly coupled to each other and accordingly to PT, which converts quantity Y being controlled to the shift X2, and also to the motor shaft through the kinematic transmission KT, the shift XI in whose output changes the inductances Lz, L2. Accordingly, X2 changes Ls, La. Below, the operation of the bridge circuit is analyzed, and the linearization of its calibration curve is investigated, the distributed parameters of the inductive transducers being taken into account. When the power-supply impedance is negligibly small and that of the null-indicator large (as compared with the transducer impedance), and the resistances and inductances of the coils in the corresponding transducers are equal: Ra = R2 = Rs = R4 = R, L~ = L= = LI, and Ls = L, = LII, the equation for the voltage across the output diagonal of the bridge circuit may, according to [8], be written: