CN207036946U - A kind of current measuring device - Google Patents

A kind of current measuring device Download PDF

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Publication number
CN207036946U
CN207036946U CN201720655104.5U CN201720655104U CN207036946U CN 207036946 U CN207036946 U CN 207036946U CN 201720655104 U CN201720655104 U CN 201720655104U CN 207036946 U CN207036946 U CN 207036946U
Authority
CN
China
Prior art keywords
circuit
operational amplifier
signal amplification
processor
amplification circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN201720655104.5U
Other languages
Chinese (zh)
Inventor
严伟
姚毅
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hunan University of Humanities Science and Technology
Original Assignee
Hunan University of Humanities Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hunan University of Humanities Science and Technology filed Critical Hunan University of Humanities Science and Technology
Priority to CN201720655104.5U priority Critical patent/CN207036946U/en
Application granted granted Critical
Publication of CN207036946U publication Critical patent/CN207036946U/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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Abstract

The utility model discloses a kind of current measuring device, including signal amplification circuit, differential calculation circuit, AD conversion module, processor;The signal amplification circuit, differential calculation circuit are connected with the AD conversion module;The signal amplification circuit is connected with the differential calculation circuit;The signal amplification circuit is connected with detected circuit.The AD conversion module is connected with processor.The utility model can electric current in measuring circuit directly in parallel so that the technology of being unable to disconnecting circuit of some special occasions and micrometer electric current is accomplished, and accuracy of measurement is high.

Description

A kind of current measuring device
Technical field
The utility model is related to current measurement instrument, more particularly to during circuit board testing circuit micro-current measurement, especially There is fine prospect in terms of practical chip is designed to.
Background technology
At present, ammeter mainly is sealed in survey the method for electric current using by circuit disconnection when ammeter surveys weak current.By It is cumbersome in needing disconnecting circuit to seal in ammeter, while the split-core type meter degree of accuracy has much relations with clamp, the main big electricity of measurement Stream, low current error is very big, and the sampling mode of split-core type meter is current transformer, and universal meter is resistance sampling, current transformer The current strength of sampling precision and primary side has substantial connection, is exactly the non-linear caused of transformer iron core, electric current is smaller, by mistake Difference is bigger, so split-core type meter is more around several circles when low current is measured, allows the magnetic induction of iron core to be more than inelastic region, so Measurement can it is accurately a lot, more around number of turns reading be exactly pitch of the laps multiple, the electric current/number of turns=actual current, calculate it is cumbersome, It can not implement on low current circuit, and it is in most cases troublesome in poeration so that run into some micro current occasions larger Trouble.
Utility model content
The utility model aims to provide a kind of current measuring device, electric current in direct measuring circuit in parallel, ensures that measurement is accurate Exactness is high.
In order to solve the above technical problems, technical scheme is used by the utility model:A kind of current measuring device, including Signal amplification circuit, differential calculation circuit, AD conversion module, processor;The signal amplification circuit, differential calculation circuit with The AD conversion module connection, the AD conversion module are connected with the processor;The signal amplification circuit and the differential Counting circuit connects;The processor, signal amplification circuit are connected with ammeter AM access module;The ammeter AM access module It is connected with slowdown monitoring circuit to be checked.
The ammeter AM access module includes change-over switch;The change-over switch and the measurement electricity of ammeter AM access module Hold, the measurement resistance of slowdown monitoring circuit to be checked is sequentially connected;Described change-over switch one end, measurement resistance one end of ammeter AM access module It is respectively connected to the resistance both ends to be measured of the slowdown monitoring circuit to be checked;The measurement electric capacity both ends input with the signal amplification circuit End connection.
The differential calculation circuit includes the first operational amplifier (i.e. high speed voltage follower), the second operational amplifier; The first operational amplifier negative input end is connected (i.e. high speed voltage follower) with first operational amplifier output terminal;Institute The first operational amplifier positive input terminal is stated to be connected with the signal amplification circuit output end;First operational amplifier output terminal It is connected by electric capacity with the second operational amplifier negative input end;The second operational amplifier positive input terminal passes through the first electricity Resistance ground connection;The second operational amplifier negative input end connects second operational amplifier output terminal by second resistance;It is described Second operational amplifier output terminal connects the AD conversion module.
First operational amplifier is used as high speed voltage follower;The first operational amplifier negative input end and described first Operational amplifier output terminal connects, that is, forms high speed voltage follower.
Second operational amplifier output terminal connected AD conversion module and connects the processor.
Compared with prior art, had the beneficial effect that possessed by the utility model:The utility model can directly simultaneously translocation Measure electric current in circuit, it is not necessary to disconnecting circuit can micrometer electric current, and accuracy of measurement is high.
Brief description of the drawings
Fig. 1 is the example structure block diagram of the utility model one;
Fig. 2 is the rough schematic view that the embodiment current measurement AM access module of the utility model one is measured circuit under test;
Fig. 3 is active linear circuit reduction figure after switch switch closures;
Active linear circuit reduction figure after Fig. 4 disconnects for switch switch;
Fig. 5 is the embodiment use principle figure of the utility model one;
Fig. 6 is the utility model differential calculation circuit theory diagrams.
Embodiment
As shown in Figure 1-Figure 3, the utility model embodiment signal amplification circuit, differential calculation circuit, AD conversion module, place Manage device;The signal amplification circuit, differential calculation circuit are connected with the AD conversion module;The signal amplification circuit and institute State the connection of differential calculation circuit;The processor, signal amplification circuit are connected with detected circuit.
Switch is switched in Fig. 2, electric capacity C, resistance A pass through the selection of Exact Analysis, primary circuit will not be produced in measurement The raw influence not allowed.
Any active linear circuit can be simplified to such as Fig. 4.
After switching switch closures, circuit structure such as Fig. 3, the differential equation of circuit is as follows:
Switch after switch disconnects, circuit structure such as Fig. 4, the differential equation of circuit is as follows:
By 1. 2. obtaining:
3. middle Y (circuit under test resistance M both end voltages give processor after being measured by AD conversion module when switching off), C (current measurement access part measurement electric capacity C can artificially be can adjust known to its value by gear), A (survey by current measurement access part Amount resistance R can artificially be can adjust known to its value by gear), it is known that (current measurement access part measures electricity after switch closure and U Hold C both end voltages),(AD conversion module and the measurement data COMPREHENSIVE CALCULATING of processor collaboration differential calculation circuit can obtain), Changing over time available circuit, accurately measurement obtains, and measures U in T1 the and T2 times respectively,3. program is write in substitution Solve M and R.Finally understand I surveys=Y/M.Shown by display portion.
The utility model use principle is analyzed as follows:
1. probe A (change-over switch switch one end) and probe B (measurement resistance A one end) are accessed into circuit under test first, As shown in figure 5, processor control change-over switch switch disconnects, circuit becomes structure shown in Fig. 4, now amplifies electricity by signal Road, differential calculation circuit, AD conversion module sample to resistance M both end voltages Y to be measured, as data transfer to processor Storage.
2. the closure switch switch under processor control signal, circuit structure become structure shown in Fig. 3, now the time be T0, electric capacity both end voltage size u1 is sampled in time t1, processor storage is sent into, then at the t2 moment to c both ends Voltage u2 is sampled, and is sent into processor, and simultaneous processor counts the lower Δ T=t2-t1 of record value, calculates Δ U=u2- in time U1, then calculate first group of Δ U/ Δs T=dU/dt=s1 (allow herein Δ t level off to several delicate orders of magnitude).
3. being sampled in time t3 to electric capacity both end voltage size u1, processor storage is sent into, then at the t4 moment C both end voltages u2 is sampled, is sent into processor, simultaneous processor counts the lower Δ T=t4-t3 of record value, calculates Δ U in time =u2-u1, then calculate second group of Δ U/ Δs T=dU/dt=s2 (allow herein Δ t level off to several delicate orders of magnitude).
3. the U that will be measured, s1, s2 substitute into above-mentioned equation.
4. processor solves M1 by the program write, and M1 is stored.M1 is first time sampled measurements preprocessor The data of M values in the first group of circuit under test drawn.Mn is the n-th group circuit under test that first time sampled measurements preprocessor is drawn The data of middle M values.
... (repeating 2. 3. to walk n times, obtain Mn storages respectively)
5. program calculates M=(M1+M2+M3+ ... Mn)/n, (n obtains the actual feelings of voltage swing by program depending on 1. middle measurement Condition control control, magnitude of voltage are directly proportional to n), final program calculates I surveys=Y/M.And by showing that simultaneous manual control module is shown Out.Gear etc. can be changed taking human as peripheral operation is carried out according to actual conditions simultaneously.

Claims (4)

1. a kind of current measuring device, it is characterised in that including signal amplification circuit, differential calculation circuit, processor;The letter Number amplifying circuit, differential calculation circuit are connected with the processor;The signal amplification circuit and the differential calculation circuit Connection;The signal amplification circuit is connected with ammeter AM access module;The ammeter AM access module is connected with slowdown monitoring circuit to be checked.
2. current measuring device according to claim 1, it is characterised in that the ammeter AM access module is opened including conversion Close;The change-over switch is sequentially connected with measurement electric capacity, measurement resistance;Described change-over switch one end, measurement resistance one end difference Access the resistance both ends to be measured of the slowdown monitoring circuit to be checked;The measurement electric capacity both ends connect with the signal amplification circuit input Connect.
3. current measuring device according to claim 2, it is characterised in that the differential calculation circuit includes the first computing Amplifier, the second operational amplifier;The first operational amplifier negative input end connects with first operational amplifier output terminal Connect;The first operational amplifier positive input terminal is connected with the signal amplification circuit output end;First operational amplifier Output end is connected by electric capacity with the second operational amplifier negative input end;The second operational amplifier positive input terminal passes through First resistor is grounded;The second operational amplifier negative input end connects second operational amplifier by second resistance and exported End;Second operational amplifier output terminal connects AD conversion module.
4. current measuring device according to claim 3, it is characterised in that second operational amplifier output terminal is connected Cross AD conversion module and connect the processor.
CN201720655104.5U 2017-06-07 2017-06-07 A kind of current measuring device Expired - Fee Related CN207036946U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201720655104.5U CN207036946U (en) 2017-06-07 2017-06-07 A kind of current measuring device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201720655104.5U CN207036946U (en) 2017-06-07 2017-06-07 A kind of current measuring device

Publications (1)

Publication Number Publication Date
CN207036946U true CN207036946U (en) 2018-02-23

Family

ID=61470642

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201720655104.5U Expired - Fee Related CN207036946U (en) 2017-06-07 2017-06-07 A kind of current measuring device

Country Status (1)

Country Link
CN (1) CN207036946U (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112379323A (en) * 2020-11-05 2021-02-19 山东山大电力技术股份有限公司 Equivalent simulation generator based on Rogowski coil characteristics and electronic equipment

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112379323A (en) * 2020-11-05 2021-02-19 山东山大电力技术股份有限公司 Equivalent simulation generator based on Rogowski coil characteristics and electronic equipment

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GR01 Patent grant
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20180223

Termination date: 20190607

CF01 Termination of patent right due to non-payment of annual fee