CN101126770A - Cai's circuit inductor current oscilloscope display circuit - Google Patents

Abstract

The utility model discloses an oscilloscope display circuit for the inductor current in Chua's circuit, which is characterized in that: the voltage relating to the current IL of the inductor L in the Chua's circuit (1) is reflected on the arm of the inductor L and is transferred to a reverse integrator (3) via a voltage follower (2) of the conversion circuit; the output voltage variable is proportional to the inductor current, thus the current-to-voltage conversion is realized and displayed on an oscilloscope (4). The utility model can directly measure and display the current flow of the Chua's circuit by an oscilloscope; the numbers of the three Chua's circuit waveforms which can be measured and displayed by the oscilloscope is enlarged from two to three, and the numbers of the three Chua's circuit phase diagrams also is enlarged to three compared with the original number two; thereby the oscilloscope is suitable for the debugging of the Chua's circuit and is more suitable for the teaching of the college chaos experiment and the demonstration of the science popularization chaos experiment in Chua's circuit.

Description

Cai's circuit inductor current oscilloscope display circuit

Technical field

The invention belongs to non-linear circuit, often claim chaos circuit, relate to the oscillograph display circuit of cai's circuit inductor current.

Background technology

Cai's circuit is a chaos circuit, and the third-order self-governing circuit by linear resistance, electric capacity, inductance and non-linear " Cai Shi diode " are formed satisfies the condition that can produce chaos.As shown in Figure 1.The physical quantity that 3 variations are arranged in the cai's circuit: voltage V _C1, voltage V _C2With electric current I _L, voltage V _C1With voltage V _C2Can use oscillograph to show observation, and electric current I _LJust can not use oscillograph to show observation, so, oscillograph can only show in the cai's circuit two waveforms in three waveforms.For phasor, three waveforms can be combined into three phasors, i.e. V in twos in the cai's circuit _C1-V _C2Phasor, V _C1-I _LPhasor, I _L-V _C2Phasor, oscillograph can only show V _C1-V _C2Phasor, and can not show V _C1-I _LWith I _L-V _C2Phasor, this is the defective that the cai's circuit oscillograph shows observation procedure.

Summary of the invention

The objective of the invention is to address the above problem: provide a kind of oscillograph that makes can measure three waveforms that show in the cai's circuit, and the cai's circuit inductor current oscilloscope display circuit of three phasors.

The technical solution adopted for the present invention to solve the technical problems is: with the electric current I of cai's circuit inductor L _LThe voltage that reflects on the arm of inductor L, the voltage follower by change-over circuit is delivered to the reverse integral device, output and inductor current I _LThe voltage quantities that is directly proportional realizes the current-voltage conversion, shows by oscillograph.

Described voltage follower is an arm that is connect the inductor of tested cai's circuit by first operational amplifier in-phase input end, and inverting input and output terminal connect and compose; Described reverse integral device is to be made of resistance, electric capacity and second operational amplifier, wherein first operational amplifier output terminal connects resistance, the other end of resistance connects second operational amplifier inverting input, second operational amplifier in-phase input end ground connection is connected electric capacity between second operational amplifier inverting input and output terminal.

The invention has the beneficial effects as follows: can directly use oscilloscope measurement to show the inductor current amount of cai's circuit, make oscillograph expand three waveforms to by original two waveforms that show in the cai's circuit in three waveforms of only can measuring, thereby expand three phasors to by the original phasor that shows in the cai's circuit of only can measuring, be applicable to the debugging of cai's circuit, more be applicable to the university's experimental teaching and the scientific popularization experimental demonstration of cai's circuit.

Description of drawings

Fig. 1 is the circuit theory diagrams of basic cai's circuit;

Fig. 2 is the cai's circuit inductor current oscilloscope display circuit block scheme;

Fig. 3 is the circuit theory diagrams of cai's circuit inductor current oscilloscope display circuit embodiment 1;

Fig. 4 is cai's circuit and I _LMeasure the connected system figure of display circuit embodiment 1;

Fig. 5 is cai's circuit and I _LMeasure the connected system figure of display circuit embodiment 2;

Fig. 6 is cai's circuit and I _LMeasure the connected system figure of display circuit embodiment 3;

Fig. 7 is the waveform that measures of side circuit and the oscillograph display photos of phasor.

Embodiment

Cai's circuit as shown in Figure 1 is a known circuit, does not describe at this.

As shown in Figure 1 and Figure 2, the present invention is connected current-voltage conversion circuit between existing cai's circuit 1 and oscillograph 4, and current-voltage conversion circuit is to be made of voltage follower 2 and inverting integrator 3, the electric current I of cai's circuit 1 inductor L _LThe voltage V that on the arm of inductor L, reflects _C2, be inductor L electric current I _LDifferential and be in the other direction, V _C2Be sent to reverse integral device 3,3 couples of V of reverse integral device through voltage follower 2 undistortedly _C2Carry out reverse integral and obtain I _LInitial value, output with inductor current I _LThe voltage quantities that is directly proportional realizes the current-voltage conversion, shows by oscillograph 4.

Embodiment 1 is with reference to Fig. 3, Fig. 4, and described current-voltage conversion circuit is formed first operational amplifier U by two operational amplifiers, a resistance and an electric capacity ₁In-phase input end connects the arm of the inductor L of tested cai's circuit, and inverting input and output terminal connect and compose voltage follower 1; First operational amplifier U ₁Output terminal connects resistance R ₁, resistance R ₁The other end connect second operational amplifier U ₂Inverting input, second operational amplifier U ₂In-phase input end ground connection is at second operational amplifier U ₂Be connected capacitor C between inverting input and the output terminal ₃, resistance R ₁, capacitor C ₃With second operational amplifier U ₂Constitute 3, the second operational amplifier U of reverse integral device ₂Output terminal is connected with the signal measurement probe of oscillograph 4.

The course of work: the metering circuit system as shown in Figure 4, the left side circuit is a cai's circuit, intermediate circuit is the oscillograph display circuit of cai's circuit inductor current, the right side is an oscillograph.In the cai's circuit formula, the formula of describing the inductor circuit relation is:

${\mathrm{<figure-callout\; id="2"\; label="V\; C"\; filenames="A20071001848200081.png"\; state="\{\{state\}\}">V</figure-callout>}}_C=-L\frac{{\mathrm{dI}}_L}{\mathrm{dt}}$

Inductor voltage V _C2Direct-connected is voltage follower, and input impedance is very high, is used to alleviate the load of metering circuit for cai's circuit.

Integrator circuit output-input the relation formula that is connected with voltage follower is:

$V_{\mathrm{OUT}}=-\frac{1}{{\mathrm{<figure-callout\; id="3"\; label="C"\; filenames="A20071001848200081.png"\; state="\{\{state\}\}">C</figure-callout>}}_3}{\&Integral;i}_{\mathrm{<figure-callout\; id="3"\; label="C"\; filenames="A20071001848200081.png"\; state="\{\{state\}\}">C</figure-callout>}3}\mathrm{dt}=-\frac{1}{{\mathrm{<figure-callout\; id="3"\; label="C"\; filenames="A20071001848200081.png"\; state="\{\{state\}\}">C</figure-callout>}}_3}\&Integral;\frac{1}{R_1}{V}_{\mathrm{in}}\mathrm{dt}=-\frac{1}{R_1{\mathrm{<figure-callout\; id="3"\; label="C"\; filenames="A20071001848200081.png"\; state="\{\{state\}\}">C</figure-callout>}}_3}\&Integral;-L\frac{{\mathrm{di}}_L}{\mathrm{dt}}\mathrm{dt}=\frac{L}{R_1{\mathrm{<figure-callout\; id="3"\; label="C"\; filenames="A20071001848200081.png"\; state="\{\{state\}\}">C</figure-callout>}}_3}\&Integral;\frac{{\mathrm{di}}_L}{\mathrm{dt}}\mathrm{dt}=\frac{L}{R_1{C}_3}{i}_L$

Realized the current-voltage conversion.

As shown in Figure 7, be the waveform that measures of side circuit and the oscillograph display photos of phasor.The oscilloscope measurement of circuit time domain waveform shows that wherein Fig. 7 (a) is V shown in Fig. 7 (a)～(c) _C1Voltage waveform, Fig. 7 (b) is V _C2Voltage waveform, Fig. 7 (c) is I _LCurrent waveform; The oscilloscope measurement of circuit phasor shows that wherein Fig. 7 (d) is V shown in Fig. 7 (d)～(f) _C1-V _C2Phasor, Fig. 7 (e) is V _C1-I _LPhasor, Fig. 7 (f) is I _L-V _C2The oscilloscope measurement that phasor, circuit chaos develop phasor shows that wherein Fig. 7 (g) is V shown in Fig. 7 (g)～(1) _C1-V _C2In the phasor cycle one, Fig. 7 (h) is V _C1-V _C2In the phasor cycle two, Fig. 7 (i) is V _C1-V _C2In the phasor cycle four, Fig. 7 (j) is V _C1-V _C2Single vortex of phasor cycle, Fig. 7 (k) is V _C1-V _C2In the phasor cycle three, Fig. 7 (1) is V _C1-V _C2The phasor binary vortices.As seen from the figure, embodiment 1 circuit has been realized the validity of circuit of the present invention fully.

Embodiment 2 is with reference to Fig. 5, and described current-voltage conversion circuit is formed first triode T by two triodes, 4 resistance and an electric capacity ₁Base stage connects the arm of the inductor L of tested cai's circuit, first triode T ₁Collector connects positive supply, first triode T ₁Emitter is by resistance in series R ₂Connect negative supply, first triode T ₁, resistance R ₂Constitute voltage follower 2; First triode T ₁Emitter connects resistance R ₃, resistance R ₃The other end connect second triode T ₂Base stage, second triode T ₂Base stage and collector between be connected capacitor C ₄Second triode T ₂Collector by resistance in series R ₄Connect positive supply, second triode T ₂Emitter by resistance in series R ₅Connect negative supply, by second triode T ₂, capacitor C ₄And resistance R ₃, resistance R ₄, resistance R ₅Constitute 3, the second triode T of reverse integral device ₂Output terminal is connected with oscillographic signal measurement probe.

Embodiment 2 circuit can be realized the validity of circuit of the present invention equally.

Embodiment 3 is with reference to Fig. 6, and described current-voltage conversion circuit is formed first field effect transistor BT by two field effect transistor, 4 resistance and an electric capacity ₁Grid connects the arm of the inductor L of tested cai's circuit, first field effect transistor BT ₁Drain electrode connects positive supply, first field effect transistor BT ₁Source electrode by resistance in series R ₆Connect negative supply, first field effect transistor BT ₁, resistance R ₆Constitute voltage follower 2; First field effect transistor BT ₁Source electrode connects resistance R ₇, resistance R ₇The other end connect second field effect transistor BT ₂Grid, second field effect transistor BT ₂Grid with the drain electrode between be connected capacitor C ₅Second field effect transistor BT ₂Drain electrode by resistance in series R ₈Connect positive supply, second field effect transistor BT ₂Source electrode by resistance in series R ₉Connect negative supply, by second field effect transistor BT ₂, capacitor C ₅And resistance R ₇, resistance R ₈, resistance R ₉Constitute 3, the second field effect transistor BT of reverse integral device ₂Output terminal is connected with oscillographic signal measurement probe.

Embodiment 3 circuit can be realized the validity of circuit of the present invention equally.

Claims (4)

1. a cai's circuit inductor current oscilloscope display circuit is characterized in that: with the electric current I of cai's circuit (1) inductor L _LThe voltage that on the arm of inductor L, reflects, the voltage follower (2) by change-over circuit is delivered to reverse integral device (3), and the voltage quantities that output is directly proportional with inductor current realizes current-voltage conversion, shows by oscillograph (4).

2. cai's circuit inductor current oscilloscope display circuit according to claim 1 is characterized in that: described voltage follower (2) is by first operational amplifier (U ₁) in-phase input end connects an arm of the inductor (L) of tested cai's circuit, inverting input and output terminal connect and compose; Described reverse integral device (3) is by resistance (R ₁), electric capacity (C ₃) and second operational amplifier (U ₂) constitute first operational amplifier (U ₁) output terminal connection resistor (R ₁), resistance (R ₁) the other end connect second operational amplifier (U ₂) inverting input, second operational amplifier (U ₂) in-phase input end ground connection, at second operational amplifier (U ₂) be connected electric capacity (C between inverting input and the output terminal ₃).

3. cai's circuit inductor current oscilloscope display circuit according to claim 1 is characterized in that: described voltage follower (2) is by first triode (T ₁), resistance (R ₂) constitute first triode (T ₁) base stage meets an arm of the inductor (L) of tested cai's circuit, first triode (T ₁) collector connects positive supply, first triode (T ₁) emitter one tunnel connects output terminal, another road is by resistance in series (R ₂) connect negative supply; Described reverse integral device (3) is by second triode (T ₂), electric capacity (C ₄) and resistance (R ₃), resistance (R ₄), resistance (R ₅) constitute first triode (T ₁) emitter connection resistance (R ₃), resistance (R ₃) the other end connect second triode (T ₂) base stage, second triode (T ₂) base stage and collector between be connected electric capacity (C ₄); Second triode (T ₂) emitter by resistance in series (R ₅) connect negative supply, second triode (T ₂) collector lead up to resistance in series (R ₄) connecing positive supply, its another road is an output terminal.

4. cai's circuit inductor current oscilloscope display circuit according to claim 1 is characterized in that: described voltage follower (2) is by first field effect transistor (BT ₁), resistance (R ₆) constitute first field effect transistor (BT ₁) grid meets an arm of the inductor (L) of tested cai's circuit, first field effect transistor (BT ₁) draining connects positive supply, first field effect transistor (BT ₁) source electrode by resistance in series (R ₆) connect negative supply; Described reverse integral device (3) is by second field effect transistor (BT ₂), electric capacity (C ₅) and resistance (R ₇), resistance (R ₈), resistance (R ₉) constitute first field effect transistor (BT ₁) source electrode connection resistance (R ₇), resistance (R ₇) the other end connect second field effect transistor (BT ₂) grid, second field effect transistor (BT ₂) grid and second field effect transistor (BT ₂) drain electrode between connect electric capacity (C ₅); Second field effect transistor (BT ₂) source electrode by resistance in series (R ₉) connect negative supply, second field effect transistor (BT ₂) drain electrode lead up to resistance in series (R ₈) connecing positive supply, its another road is an output terminal.

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