SU998967A1 - Electric bridge - Google Patents

Description

(54) ELECTRIC- BRIDGE

The invention is intended to be used in information measurement technology, automation, and industrial electronics for measuring the four components of a multi-element two-port network.

Known electric bridge, is -. useful for measuring the components of a multi-element two-port network. The bridge contains a power generator, a comparison arm, made according to the replacement scheme of the object under investigation, and the shoulders of the bearing are exemplary elements of one character. The bridge is powered by two signals: constant and alternating voltages or two alternating voltages of different frequencies JTl.

However, such an electric bridge allows only three components of a two-pole network to be measured.

The closest technical solution to the invention is an electric bridge, which contains a power generator, a comparison arm, made according to a circuit identical to the circuit of the object under study, and resistors are included in the shoulders of the relation. The electric bridge is balanced by two capacitors and two variables.

resistors. The bridge is powered by a trapezoidal pulse generator 2).

A disadvantage of the known bridge is the low accuracy of the measurement of the pair-ieTpoB multi-element terminal due to its balancing with variable capacitors.

The purpose of the invention is to improve the measurement accuracy of the components of a multi-element two-port network.

The goal is achieved by the fact that in an electric bridge containing a trapezine generator, a Ceydal ForFsh, connected to the supply diagonal, one branch of the bridge is formed by series-connected objects of measurement and the first resistor, the junction point of which

Claims (2)

20 forms the first vertex of the measuring diagonal, the object of measurement is made in the form of a two-terminal circuit with a four-cell replacement circuit consisting of two parallel circuits, one of which contains a second resistor, and the second is the first capacitor to which the third resistor is connected in series and the second capacitor, the other branch of the bridge, is made in the form of a fourth resistor connected in series and the first variable resistor, in parallel to which a circuit is connected, is an IchE of The third capacitor, the second and the third variable resistors, are connected in parallel to the second variable resistor in series with a fourth capacitor and a fourth variable resistor, the junction point of which forms the second vertex of the measuring diagonal of the bridge. FIG. 1 is a diagram of an electric bridge; in fig. 2 a, b -. pulse form, voltage respectively at the input and output of the bridge. The electric bridge (Fig 1) contains a power generator 1 of trapezoidal pulses, a measurement object consisting of a resistor 2 (R2 in parallel with which capacitor 3 (Sz) is connected and in series with parallel connected resistor 4 of CR4) and 5 CC5} . The object of measurement with series-connected resistor) shoulder; The ratio forms the first branch of the bridge. The second branch of it contains a capacitor 7 (C7), subsequently connected to which are sequentially connected capacitor 8 (C8), variable resistor 9 (R9) in parallel with which the variable resistor 10 (R10) is connected in parallel, and a variable resistor 11 (R11 ). In parallel with respect to all the listed elements of the second branch of the bridge, a variable resistor 12 (R12) is turned on. In the second ratio plate, a resistor 13 is turned on (R13 Balancing of the electric bridge occurs as follows. When a trapezoidal flat tip of the pulse is applied from generator 1 in a steady state, zero currents are established through capacitors 3 and 7. Therefore, these capacitors and elements 4-11 do not affect voltage impulses in the measuring diagonal of the bridge.The change in the resistance value of the resistor 12 causes the flat top of the voltage impulse in the measuring diagonal to zero, i, e, balance the bridge by oh of its components. As a result, the voltage pulse in the measuring diagonal takes the form shown in fig. 26. When exposed to a linearly changing part of the bridge supplying pulse after the termination of transients through capacitors 3 and 7, a constant current, the value of which depends on the values of their capacitances. By changing the value of the resistor 11, the flat peak of the pulse in the measuring diagonal of the bridge in its second section leads to zero, i, e. the bridge is balanced by its other component. The remaining voltage pulse surge in the output diagonal of the bridge results in zero alternating adjustment of the resistance values of resistors 9 and 10. Now, for the entire duration of the trapezoidal feed pulse, the voltage in the bridge diagonal is zero. After equilibration, four parameters of the multi-element two-port network are counted, RQ -. ra.ClCR-HR-ll- -R-iVR..R-) R- (1 on p, R4-CT PsIOtlC Mg Mg Rfe-C8-R9 (.R. R1) 3 Ce-Cb Cf-Rtl.Rfe (R94R) -4: 1 (.Ш-Ц11.) 1 TT -WO tcb-R A1-Rfo - eg .R9 CRia-v Ri) 1 As can be seen from the description of the work, the bridge has a separate balancing in two out of four Parameters. The polarity of the voltage pulse in the measuring diagonal of the bridge once and for all determines the direction of the balance. The electric bridge comprising a trapezoidal pulse generator connected to the supply diagonal, one branch of the bridge is formed by series-connected object of measurement and the first resistor, the junction point of which forms the first vertex of the measuring diagonal; of two parallel circuits, the first of which contains the second resistor, and the second - the first capacitor, which is connected in series Parallel connected third resistor and second capacitor, characterized in that, in order to improve the measurement accuracy of the components of a multi-element two-port network, the other branch of the bridge is made of a fourth resistor connected in series and a first variable resistor in parallel to which is connected the capacitor, the second and third variable resistors, parallel to the second variable resistor are connected in series connected fourth capacitor and fourth variable resistor, the junction point of which forms the second vertex of the measuring diagonal. Sources of information taken into account in the examination 1, USSR Author's Certificate 413430, cl. G01R 17/10, 1974, i J u ti-D 2. Moor V.F., Peredelsky G.I. Analysis of the bridge circuit to measure the four composition of the advanced multi-element two-port network. Sat Methods and means of signal conversion in scientific instrument making. Krasnoyarsk, Siberian Branch of the USSR Academy of Sciences, 1979, p. 38 - 41 prototype). / 2 i5 × //