RU2141672C1 - Electric bridge for measuring n-port network parameters - Google Patents

Abstract

FIELD: physical quantities measurement technology. SUBSTANCE: bridge has series- connected pulse train generator 1 with voltage varying within pulse length obeying K_ot^°,K₁t′,K_n-1t^n-1 law, where K₀,K₁ are constants; t is time; electric bridge; and null-indicator 29. Generator has pulse shapers 2, 3, 4, ... with voltage varying to obey power function law, switch 6, and power amplifier 6. In-step operation of pulse shapers and null-indicator is ensured by synchronizing unit 7 provided in generator. Bridge circuit including equipment under measurement has ratio-arm resistor 22 and two terminals for connecting equipment under measurement; common lead of resistor and one of terminals forms first lead of bridge output. Bridge circuit including equalizing (adjustable) resistors has ratio-arm resistor 8 connected in series with circuit set up of parallel-connected resistor 9 and network of series-connected capacitor 10 and two resistors 11, 12. Novelty is introduction of branch incorporating equalizing resistors of bridge of n-3 similar increment circuits, where n is number of components in equivalent circuit of equipment under measurement. Each increment circuit has series-connected capacitor (say, 19), first and second resistors (say, 20, 21). Capacitor (say, 19) of each next increment circuit is connected to common lead of capacitor (say, 16) and first resistor (say, 17) of preceding circuit, and its second resistor (say, 21), to common lead of two resistors (say, 17, 18) of preceding increment circuit. Common lead of two resistors (say, 20, 21) of last increment circuit forms second lead of bridge output. EFFECT: enlarged functional capabilities. 1 dwg

Description

 The invention relates to information-measuring equipment, industrial electronics, automation and can be used to control and determine the parameters of measurement objects containing active resistances and capacities in the equivalent circuit, as well as physical quantities by means of parametric sensors included in the electric bridge.

 A well-known bridge meter of the parameters of n-element passive two-terminal [1], containing a pulse generator of complex shape, four-arm electric bridge, the two adjacent arms of the relationship of which are included one resistor, and two comparison arms form n-element two-terminal from resistors and capacitors and zero indicator, the generator output is connected to the diagonal of the bridge power, and its measuring diagonal is connected to the input of the zero indicator.

 Its disadvantage is the inability to balance the bridge circuit only with adjustable resistors.

 Known electric bridge [2], which contains a trapezoidal pulse generator connected to the diagonal of the power supply of the bridge circuit, the first branch of which is formed by the resistance shoulder resistor and the measurement object, the second branch is a complex circuit, where only adjustable resistors are used as balancing elements.

 Its disadvantage is the lack of separate balancing in two of the four measured parameters.

 The closest in technical essence and the achieved result to the claimed device is an electric bridge selected as a prototype [3], containing a complex pulse generator, a bridge circuit, one branch of which is formed by a resistor of the relationship arm and the measurement object connected in series, the other branch is a complex circuit, where only adjustable resistors are used as balancing elements, the generator is connected to the input of the bridge circuit, and its output is connected to the zero-indicator input pa.

 Its disadvantage is the inability to separately balance the bridge circuit only with adjustable resistors when determining more than three parameters of the measurement object, which narrows its functionality.

 The problem to which the invention is directed, is to expand the functionality of the electric bridge while separately balancing it only with adjustable resistors.

This is achieved by the fact that in a bridge meter of parameters of n-element two-terminal devices containing a pulse generator, which consists of pulse shapers with a change in voltage over their duration according to the law K ₀ t ⁰ , K ₁ t ¹ , K ₂ t ² , ... , K _n-1 t ^n-1 (where K ₀ , K ₁ , K ₂ ... are constant coefficients, t is time), a switch whose inputs are connected to the outputs of the shapers, and the output is connected to a power amplifier, the output of which forms the first output of the pulse generator, the synchronization unit, the outputs of which are connected to the inputs of the synchronization forms rovateley, and one of its output forms a second output of the generator (synchronization yield); the generator is connected to the input of the electric bridge, the first of two branches of which is formed by the resistor of the relationship arm, in series with which is connected a complex circuit consisting of a parallel-connected resistor and a circuit of series-connected capacitor and two resistors, the second branch of the bridge consists of a resistor of the second relationship arm and two terminals for connecting the measurement object, which, in particular, consists of a parallel connected resistor and capacitor, a second condensate is connected in series relative to them Oh, a second resistor is connected in parallel to this group, and a third capacitor is connected in series, and a third resistor is connected in parallel to the resulting circuit, one bridge input terminal forms the general output of a complex circuit in the first branch and one of the terminals for connecting the measurement object in the second branch, the second terminal of this input grounded and formed by the common conclusion of two resistors of the shoulders of the relationship in different branches; a zero indicator, one input of which (synchronization input) is connected to the second output of the generator, and one terminal of the second input is connected to the common terminal of the shoulder resistor of the second branch and the second of the terminals for connecting the measurement object, this common terminal forms the first terminal of the bridge output; the common bus of the indicator and the common bus of the generator are connected to the ground, n-3 identical building circuits are introduced into the complex circuit of the first branch of the bridge, where n is the number of elements in the equivalent circuit of the measurement object, each building circuit consists of a series-connected capacitor, the first and second resistors, the capacitor of each subsequent extension circuit is connected to the common terminal of the capacitor and the first resistor of the previous circuit, and its second resistor is connected to the common terminal of two resistors of the previous extension circuit, the common terminal of two resistors in the latter chain extension forms the second terminal of the bridge and the output connected to the second input terminal of the second zero indicator; the number of formers in the generator is equal to the number of elements in the equivalent circuit of the measurement object (n).

The invention is illustrated in the drawing. The bridge meter of the parameters of n-element two-terminal devices contains a pulse generator 1, which consists of the required number of pulse shapers with voltage change over their duration according to the law of power functions, in particular, a rectangular pulse shaper 2 (K ₀ t ⁰ ), a linear pulse shaper variable voltage 3 (K ₁ t ¹ ), quadratic pulse train driver 4 (K ₂ t ² ), etc. The generator also includes a switch 5, a power amplifier 6, and a sync block ronization 7. The common bus of the generator is connected to the ground. The output of the power amplifier 6 forms the first output of the generator 1, and one of the outputs of the synchronization unit 7 forms its second output (synchronization output). The first branch of the electric bridge includes a relationship arm resistor 8 (R8) and a complex circuit of a resistor 9 (R9), a capacitor 10 (C 10), a resistor 11 (R11), a resistor 12 (R12), a capacitor 13 (C 13), resistor 14 (R14), resistor 15 (R15), capacitor 16 (C 16), resistor 17 (R17), resistor 18 (R18), capacitor 19 (C 19), resistor 20 (R20) and resistor 21 (R21). The common output of the resistors 20 and 21 forms one of the outputs of the bridge output. The second branch of the bridge is formed by the resistor 22 (R22) of the shoulder of the relationship and terminals for connecting the measurement object. In particular, it comprises a resistor 23 (R23), a capacitor 24 (C24), a resistor 25 (R25), a capacitor 26 (C26), a resistor 27 (R27), and a capacitor 28 (C28). The total output of the resistor 22 of the shoulder of the relationship and one of the terminals for connecting the measurement object forms the second output terminal of the bridge. The general output of a complex circuit in the first branch and another terminal for connecting the measurement object of the second branch forms the first output of the bridge input and is connected to the first output of the pulse generator. The second output of the bridge input is grounded and is formed by the common output of two resistors 8 and 22 of the arms of the relationship of different branches. The first input of the zero indicator 29 is connected to the output of the bridge, and its second input (synchronization input) is connected to the second output of the pulse generator 1.

A bridge meter for the parameters of n-element two-terminal devices works as follows. In the initial state, the voltages at the input and output of the electric bridge are equal to zero. By means of the switch 7, we first supply a rectangular pulse train to the bridge from the generator 1. Under the influence of the next pulse in the steady state, unchanging voltages are established in the branches of the bridge. The nonequilibrium voltage here depends only on the values of the resistances of the resistors 8, 9, 22, and 23, since the capacitances in this case represent an open circuit. The first condition for the equilibrium of the bridge:
R ₈ R ₂₃ -R ₉ R ₂₂ = 0
By a single adjustment of the resistance value of the balancing resistor 9 (R9), the flat peak of the impulse nonequilibrium signal is brought to zero, thereby fulfilling the first equilibrium condition of the bridge (1). The equilibrium of the bridge here and in the future is noted by the oscilloscope (29) (zero indicator). Next, through the switch 7, we feed a sequence of pulses of linearly varying voltage to the bridge from the generator 1. When the next such pulse is applied, at the bridge output after the end of the transient process, a pulse nonequilibrium signal with a flat top is established. The second condition for the equilibrium of the bridge:
C ₁₀ (R ₈ R ₉ + R ₉ R ₁₂ + R ₉ R ₁₂ ) -C ₂₄ R ₉ R ₂₂ = 0
You can perform it by adjusting the resistance values of the balancing resistors 9 (R9) and 12 (R12). But the resistor 9 is already involved in fulfilling the first equilibrium condition (1) and an attempt to regulate it will lead to a violation of this equilibrium condition, which is unacceptable. Then there is only one possibility for fulfilling the second equilibrium condition (2) - this is to adjust the balancing resistor 12. By adjusting this resistor once, we bring the flat top of the impulse nonequilibrium signal to zero, that is, we fulfill the second equilibrium condition (2). After that, through the switch 7, we feed to the bridge from the generator 1 a sequence of quadratic pulses. Under the influence of the next pulse after the end of the transition process, a pulse signal of disequilibrium with a flat top is established at the bridge output. The third condition of equilibrium has the form:
C ₁₃ R ₁₁ R ₁₅ (R ₈ + R ₉ ) + C ₂₄ R ₂₅ (R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ ) -C ₂₄ R ₂₂ R ₉ R ₁₁ = 0
Without violating the previous equilibrium conditions (1) and (2), this condition (3) can be fulfilled by adjusting the values of the resistances 11 (R11) or 15 (R15) or both of these resistances. By a single adjustment, we bring the flat peak of the impulse voltage of nonequilibrium to zero and fulfill the third equilibrium condition (3). When the impulses of all subsequent forms, except the last, act on the bridge, there are two resistances in each subsequent equilibrium condition, the adjustment of which does not violate the previous equilibrium conditions and at the same time allows the next equilibrium condition to be fulfilled, similar to the last described case. In particular, for the fourth equilibrium condition, this
C ₁₃ C ₁₆ R ₁₁ R ₁₄ R ₁₈ (R ₈ + R ₉ ) + C ₁₃ (C ₂₄ + C ₂₆ ) R ₁₁ R ₁₅ R ₂₅ (R ₈ + R ₉ ) + C ₁₃ C ₂₄ R ₂₅ (R ₁₁ + R ₁₄ + R ₁₅ ) (R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ ) -C ₂₄ R ₉ R ₁₁ R ₂₂ (C ₂₆ R ₂₅ + C ₁₃ R ₁₄ ) = 0
adjustable resistance 14 (R14) and 18 (R18), and for the fifth equilibrium condition adjustable resistance 17 (R17) and 21 (R21). At the last
C ₁₃ C ₁₆ C ₁₉ R ₁₁ R ₁₄ R ₁₇ R ₂₁ (R ₈ + R ₉ ) + C ₁₃ C ₁₆ R ₁₁ R ₁₄ R ₁₈ (R ₈ + R ₉ ) (C ₂₄ R ₂₅ + C ₂₆ R ₂₅ + C ₂₆ R ₂₇ ) + C ₁₃ R ₁₁ R ₁₅ R ₂₅ (R ₈ + R ₉ ) [C ₁₆ (C ₂₄ + C ₂₆ ) (R ₁₄ + R ₁₇ + R ₁₈ ) + C ₂₄ C ₂₆ R ₂₇ ] + C ₁₃ C ₂₄ R ₂₅ (R ₁₁ R ₁₄ + R ₁₅ ) (R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ ) (C ₁₆ R ₁₇ + C ₁₆ R ₁₈ + C ₂₆ R ₂₇ ) + C ₁₃ C ₁₆ C ₂₄ R ₁₄ R ₂₅ (R ₁₁ + R ₁₅ ) (R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ ) -C ₁₆ C ₂₄ R ₉ R ₁₁ R ₁₇ R ₂₂ (C ₂₆ R ₂₅ + C ₁₃ R ₁₄ ) - C ₁₃ C ₂₄ C ₂₆ R ₉ R ₁₁ R ₁₄ R ₂₂ (R ₂₅ + R ₂₇ ) = 0
in the form of supply pulses, that is, with the last balancing, there is only one adjustable resistance, which does not lead to a violation of the previous equilibrium conditions and allows the last equilibrium condition to be fulfilled. This is the first resistance of the last build chain. In particular, for the bridge in the drawing, such an adjustable resistance is resistance 20 (R20), which confirms the last condition of equilibrium
C ₁₀ C ₁₃ C ₁₆ C ₁₈ {R ₁₁ R ₁₄ R ₁₇ R ₂₁ (R ₈ + R ₉ ) [R ₂₅ (C ₂₄ + C ₂₆ ) + R ₂₇ (C ₂₆ + C ₂₈ )] + R ₁₁ R ₁₄ R ₁₈ (R ₈ + R ₉ ) (R ₁₇ + R ₂₀ + R ₂₁ ) (C ₂₄ R ₂₅ + C ₂₆ R ₂₅ + C ₂₆ R ₂₇ ) + C ₂₄ R ₁₄ R ₂₅ (R ₁₁ + R ₁₅ ) ( R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ ) (R ₁₇ + R ₂₀ + R ₂₁ ) + R ₁₁ R ₁₅ R ₂₅ (R ₈ + R ₉ ) (C ₂₄ + C ₂₆ ) [(R ₂₀ + R ₂₁ ) (R ₁₄ + R ₁₇ + R ₁₈ ) + R ₁₇ (R ₁₄ + R ₁₈ )] + C ₂₄ R ₂₅ (R ₁₁ + R ₁₄ + R ₁₅ ) (R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ ) [R ₁₇ (R ₂₀ + R ₂₁ ) + R ₁₈ (R ₁₇ + R ₂₀ + R ₂₁ )]} + C ₁₀ C ₁₃ C ₁₆ R ₂₅ R ₂₇ {R ₁₁ (R ₈ + R ₉ ) (C ₂₄ C ₂₆ + C ₂₄ C ₂₈ + C ₂₆ C ₂₈ ) [R ₁₄ R ₁₈ + R ₁₅ (R ₁₄ + R ₁₇ + R ₁₈ )] + C ₂₄ (C ₂₆ + C ₂₈ ) (R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ ) [R ₁₄ (R ₁₁ + R ₁₅ ) + (R ₁₁ + R ₁₄ + R ₁₅ ) (R ₁₇ + R ₁₈ )]} + C ₁₀ C ₁₃ C ₁₉ C ₂₄ C ₂₆ R ₂₅ R ₂₇ (R ₁₇ + R ₂₀ + R ₂₁ ) [R ₁₁ R ₁₅ (R ₈ + R ₉ ) + (R ₁₁ + R ₁₄ + R ₁₅ ) (R ₈ R ₉ + R ₈ R ₁₂ + R ₉ R ₁₂ )] - C ₁₀ C ₂₄ R ₉ R ₁₁ R ₂₂ {C ₁₆ R ₁₇ (C ₂₈ R ₂₇ + C ₁₉ R ₂₀ ) (C ₂₆ R ₂₇ + C ₁₃ R ₁₄ ) + C ₁₃ C ₂₆ R ₁₄ (R ₂₅ + R ₂₇ ) [C ₁₆ R ₁₇ + C ₁₉ (R ₁₇ + R ₂₀ + R ₂₁ )] + C ₂₆ R ₂₅ [C ₂₈ R ₂₇ (C ₁₃ R ₁₄ + C ₁₆ R ₁₄ + C ₁₆ R ₁₈ ) + C ₁₆ C ₁₉ R ₁₇ R ₂₀ + C ₁₆ C ₁₉ (R ₁₄ + R ₁₈ ) (R ₁₇ + R ₂₀ + R ₂₁ )]} = 0.

 Thus, this bridge meter of the parameters of n-element bipolar allows you to expand the functionality and determine the parameters 4-, 5-, 6-, etc. elemental bipolar with homogeneous reactive elements. In this case, the bridge is balanced separately only by exemplary adjustable resistors. In addition, less weight and smaller dimensions are retained, since resistance stores used as balancing elements have lower weight and dimensions compared to capacity and inductance stores.

 Sources of information taken into account during the examination.

 1. A.S. N 1150556, MKI G 01 R 17/10. Bridge meter of parameters of n-element two-terminal / G.I. Peredelsky. - publ. in BI, 1985, N14.

 2. A. p. N 998967, MKI G 01 R 17/10. Electric bridge / G.I. Peredelsky. - publ. in BI, 1983, N7.

 3. Peredelsky G.P. Switching bridge circuits. -M .: Energoatomizdat, 1988, p. 114, fig. 4.5, bridge 1 is a prototype.

Claims (1)

A bridge meter of parameters of n-element two-terminal circuits, containing a pulse generator, which consists of pulse shapers with a change in voltage over their duration according to the law K ₀ t ⁰ , K ₁ t ¹ ... K _n-1 t ^n-1 (where K ₀ , K ₁ , K ₂ ... are constant coefficients, t is time), of a switch whose inputs are connected to the outputs of the drivers, and the output is connected to a power amplifier, the output of which forms the first output of the pulse generator, a synchronization unit, the outputs of which are connected to the inputs shapers synchronization, and one of its outputs forms the second output of the pulse generator (synchronization output), the pulse generator is connected to the input of the electric bridge, the first of two branches of which is formed by the resistor of the shoulder, in series with which is connected a complex circuit consisting of a parallel-connected resistor and a circuit of series-connected capacitor and two resistors, the second branch of the electric bridge consists of a resistor of the second arm of the relationship and two terminals for connecting the object of change, which, in particular, consists of parallel to of a resistor and a capacitor, a second capacitor is connected in series relative to them, a second resistor is connected in parallel to this group, and a third capacitor is connected in series and a third resistor is connected in parallel to the resulting circuit, one output of the input of the electric bridge forms the common output of a complex circuit in the first branch and one of connecting the measurement object in the second branch, the second output of the input of the electric bridge is grounded and formed by the common output of two resistors of the arm of the relationship in different branches; a zero indicator, one input of which (synchronization input) is connected to the second output of the pulse generator, and one terminal of the second input is connected to the common terminal of the shoulder resistor of the second branch and the second of the terminals for connecting the measurement object, this common terminal forms the first terminal of the output of the electric bridge ; the common bus of the null indicator and the common bus of the pulse generator are connected to ground, characterized in that n-3 identical building circuits are introduced into the complex circuit of the first branch of the electric bridge, where n is the number of elements in the equivalent circuit of the measurement object, each building circuit consists of sequentially connected capacitor, the first and second resistors, the capacitor of each subsequent extension circuit is connected to the common terminal of the capacitor and the first resistor of the previous circuit, and the second resistor of the named subsequent extension circuit I - to the general conclusion of two resistors of the previous extension circuit, the common output of two resistors of the last extension circuit forms the second output terminal of the electric bridge and connected to the second output of the second input of the zero indicator, the number of formers in the pulse generator is equal to the number of elements in the equivalent circuit of the measurement object (n )