CN207036946U - A kind of current measuring device - Google Patents
A kind of current measuring device Download PDFInfo
- 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
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- 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
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- Measurement Of Resistance Or Impedance (AREA)
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
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.
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)
| 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 |
-
2017
- 2017-06-07 CN CN201720655104.5U patent/CN207036946U/en not_active Expired - Fee Related
Cited By (2)
| 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 |
| CN112379323B (en) * | 2020-11-05 | 2022-10-21 | 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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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 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 |