CN112630517A - Method and system for automatically switching range measurement current - Google Patents
Method and system for automatically switching range measurement current Download PDFInfo
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- CN112630517A CN112630517A CN202011415636.4A CN202011415636A CN112630517A CN 112630517 A CN112630517 A CN 112630517A CN 202011415636 A CN202011415636 A CN 202011415636A CN 112630517 A CN112630517 A CN 112630517A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
Abstract
The invention discloses a method for automatically switching range measurement current, which comprises the following steps: debugging a first measuring range measuring and conditioning circuit and a second measuring range measuring and conditioning circuit; connecting the measuring end of the first range measurement conditioning circuit to two ends of a diode D1 and a sampling resistor R1; connecting the measuring end of the second measuring range testing conditioning circuit with two ends of a sampling resistor R2; the diode D1 and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply and the load resistor RL to form a double-range current test loop. The invention also provides a system for automatically switching the measuring range and measuring the current. The invention has simple circuit, low cost and easy calculation and design; the measurement reading in the range switching process and the current passing through the load equipment are in seamless connection, so that the influence on the work of the load equipment is extremely small; the invention is very suitable for continuous and accurate measurement of dynamic change of load current, and the measurement accuracy is easily ensured by the current values at both ends no matter how violent the current change is.
Description
Technical Field
The invention relates to the technical field of measuring current, in particular to a method and a system for automatically switching measuring range measuring current.
Background
As is well known, current measurement is usually performed by connecting a sampling resistor in a current loop, obtaining a voltage across the sampling resistor through measurement, and then converting the current into a loop current. Because the current in the loop has a large variation range, and because of the limitation of the performance of the components of the existing measuring system, the precise measurement can be completed only by switching the measuring range, namely, different sampling resistors are changed to obtain a voltage signal suitable for the test. A typical circuit is shown in fig. 1, and span switching is usually pre-estimated and then manually completed, which is not intelligent and automatic enough. In addition, there is a method for automatically switching the range when the measured value cannot be estimated, or for the convenience of measurement, which is usually accomplished by controlling an electronic switch through a comparison circuit, as shown in fig. 2: however, this method has obvious disadvantages: (1) the circuit design is complex, a plurality of comparison control circuits are needed to complete the control logic of range switching, and the cost is high; (2) the semiconductor electronic switch is not completely closed when being closed, and a small leakage current influences the measurement result of the small current of uA or even lower magnitude; (3) the mechanical electronic switches such as relays and the like have the problems of slow switching, influence on the normal work of loads and measurement failure.
Based on this, there is an urgent need for a method and system for automatically switching the range measurement current, which has a simple structure and is easy to implement.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method and a system for automatically switching the range measurement current, which realize the seamless switching of the current range measurement by utilizing a diode with proper conduction current to match with a sampling resistor.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a method of automatically switching a range measurement current, comprising the steps of:
debugging a first measuring range measuring and conditioning circuit and a second measuring range measuring and conditioning circuit;
connecting the measuring end of the first range measurement conditioning circuit to two ends of a diode D1 and a sampling resistor R1;
connecting the measuring end of the second measuring range testing conditioning circuit with two ends of a sampling resistor R2;
finally, the diode D1 and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply and the load resistor RL to form a double-range current test loop.
Further: the MCU control circuit is connected with the first range measurement conditioning circuit and the second range measurement conditioning circuit in a control mode and is used for controlling the display device when measuring current.
Further: a diode D2 is also included, and a diode D2 is connected in anti-parallel with the diode D1 for measuring the alternating current.
Further: the three-range current testing circuit further comprises a third-range measuring and conditioning circuit, a diode D3, a diode D4 and a sampling resistor R3, the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel, the diode D3 and the diode D4 are connected in reverse to be used for measuring alternating current, the measuring end of the third-range measuring and conditioning circuit is connected to two ends of the diode D3, the diode D4 and the sampling resistor R3, and finally the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel and then connected with the sampling resistor R2, the sampling resistor R1, a power supply and a load resistor RL in series to form a three-range current testing loop.
Further: the three-range current testing circuit further comprises a fourth-range measuring and conditioning circuit, a diode D5 and a sampling resistor R4, the diode D5 and the sampling resistor R4 are connected in parallel, the measuring end of the fourth-range measuring and conditioning circuit is connected to the two ends of the diode D5 and the two ends of the sampling resistor R4, and finally the diode D5 and the sampling resistor R4 are connected in parallel and then connected with the sampling resistor R1, the sampling resistor R2, a power supply and a load resistor RL in series to form a three-range current testing circuit.
In order to achieve the above object, the present invention further provides a system for automatically switching a range measurement current, which includes an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a diode D1, a sampling resistor R1, a sampling resistor R2, a power supply, and a load resistor RL, wherein a measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1 and the sampling resistor R1, a measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D1 and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply, and the load resistor RL to form a dual-range current test loop, and the MCU control circuit is connected to the first range measurement conditioning circuit and the second range measurement conditioning circuit for controlling a display device during current measurement.
In order to achieve the above object, the present invention further provides a system for automatically switching a range measurement current, which includes an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a diode D1, a diode D2, a sampling resistor R1, a sampling resistor R2, a power supply, and a load resistor RL, wherein a measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1, the diode D2, and the sampling resistor R1, a measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D2 and the diode D1 are connected in reverse parallel for measuring an ac current, the diode D1, the diode D2, and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply, and the load resistor RL to form a dual-range current test loop, the MCU control circuit is connected to the first range measurement conditioning circuit and the second range measurement conditioning circuit in a control manner, for use in measuring current as a control display device.
In order to achieve the above object, the present invention further provides a system for automatically switching a range measurement current, which includes an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a third range measurement conditioning circuit, a diode D1, a diode D2, a diode D3, a diode D4, a sampling resistor R1, a sampling resistor R2, a sampling resistor R3, a power supply, and a load resistor RL, wherein a measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1, the diode D2, and the sampling resistor R1, a measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D2 is connected in reverse parallel with the diode D1 for measuring an ac current, the diode D3, the diode D4, and the sampling resistor R3 are connected in parallel, the diode D3 and the diode D4 are connected in reverse for measuring an ac current, the measuring end of the third range measuring and conditioning circuit is connected with two ends of a diode D3, a diode D4 and a sampling resistor R3, the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel and then connected with a sampling resistor R2, a sampling resistor R1, a power supply and a load resistor RL in series to form a three-range current testing loop, and the MCU control circuit is connected with the first range measuring and conditioning circuit, the second range measuring and conditioning circuit and the third range measuring and conditioning circuit in a control mode and used as a control display device when measuring current.
In order to achieve the above object, the present invention further provides a system for automatically switching a range measurement current, which includes an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a fourth range measurement conditioning circuit, a diode D1, a diode D5, a sampling resistor R1, a sampling resistor R2, a sampling resistor R4, a power supply, and a load resistor RL, wherein a measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1 and the sampling resistor R1, a measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D1 is connected in parallel to the sampling resistor R1, a measurement end of the fourth range measurement conditioning circuit is connected to two ends of the diode D5 and the sampling resistor R4, the diode D5 and the sampling resistor R4 are connected in parallel, and then connected to the sampling resistor R1, the sampling resistor R2, the power supply, and the load resistor RL in series to form a three-range current test loop, the MCU control circuit is in control connection with the first range measurement conditioning circuit, the second range measurement conditioning circuit and the fourth range measurement conditioning circuit and is used as control display equipment when measuring current.
Further: the forward conducting voltage of the diodes D1, D2, D3 and D4 is about 0.6V, and when the forward voltage is 0.1V, the forward current is 60 nA.
The invention has the beneficial effects that: the invention has simple circuit, low cost and easy calculation and design; the measurement reading in the range switching process and the current passing through the load equipment are in seamless connection, so that the influence on the work of the load equipment is extremely small; the invention is very suitable for continuous and accurate measurement of dynamic change of load current, and the measurement accuracy is easily ensured by the current values at both ends no matter how violent the current change is.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a circuit diagram of a manual switching range in the prior art;
FIG. 2 is a diagram of an automatic switching range circuit in the prior art;
fig. 3 is a schematic structural diagram of a system for automatically switching a span measurement current in embodiment 2 (direct current double span);
fig. 4 is a schematic structural diagram of a system for automatically switching a span measurement current (ac double span) in embodiment 3;
fig. 5 is a schematic structural view (ac three-range) of a system for automatically switching a range measurement current according to embodiment 4;
fig. 6 is a schematic structural diagram (dc three-range) of a system for automatically switching a range measurement current in embodiment 4.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The embodiments and features of the embodiments in the present application may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout includes three juxtapositions, exemplified by "A and/or B" including either A or B or both A and B. In addition, "a plurality" means two or more. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the invention.
See fig. 3-6.
Example 1
A method of automatically switching a range measurement current, comprising the steps of:
debugging a first measuring range measuring and conditioning circuit and a second measuring range measuring and conditioning circuit;
connecting the measuring end of the first range measurement conditioning circuit to two ends of a diode D1 and a sampling resistor R1;
connecting the measuring end of the second measuring range testing conditioning circuit with two ends of a sampling resistor R2;
finally, the diode D1 and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply and the load resistor RL to form a double-range current test loop.
In addition, when the forward voltage of the diode of this embodiment is not enough to conduct, the forward current is extremely low, and the diode can be regarded as an off state. When the voltage is much lower than the turn-on voltage, and the forward voltage is further reduced, the reduction amplitude of the forward current is larger and can be ignored when being far lower than the measured current.
As shown in fig. 3, R1 and R2 are sampling resistors for two measuring ranges of small current and large current, respectively. When the measured current is small, the voltage on the large current range sampling resistor R2 is very low and is difficult to measure, but the voltage on the small current range R1 is large enough to make accurate measurement. When the measured current is large enough, the diode is conducted, the load current is ensured to be continuous, the voltage on the R2 is large enough, and the accurate measurement can be completed by using a large current range. Thus, seamless switching of two ranges is realized.
Through practical tests, the forward conduction voltage of a diode is about 0.6V, and the forward current is only 60nA when the forward voltage is 0.1V. This is a typical characteristic of a diode. Most diodes are commonly of this nature. When small current is measured, a proper sampling resistor can be selected, so that the current is ensured to mainly flow through the resistor, and the leakage current flowing through the secondary diode can be ignored. For example, when the voltage is 0.1V, I is V/R, the current flowing through the resistor is 0.1/10, 0.01A is 10mA, and the forward current of 60nA is taken as an example when the photodiode is 0.1V, the error introduced is 60nA/10mA is 0.006%, which is completely negligible.
When the tested current is lower, the voltage at two ends of the diode is also lower, the amplitude of the reduction of the leakage current is larger due to the characteristics of the diode, and the test result is not influenced. And by selecting a larger sampling resistor resistance value, in the current measurement of uA, nA and even pA magnitude, the current is always ensured to mainly pass through the resistor, and the leakage current of the diode in the measuring range can be ignored all the time.
When the current is larger, the voltage across the resistor rises, and when the current is close to or higher than the on-voltage of the diode, the current mainly flows through the diode. At this point, the voltage reading across the first gear R1 is not meaningful, but the current through the second gear sampling resistor R2 is large enough, and the voltage is high enough, to make a measurement reading. The size of the sampling resistor of two gears can be calculated and designed, so that the two measuring range measuring ranges have an overlapping area, continuous reading of two-gear measurement can be guaranteed, and seamless switching is achieved.
In one specific example: the MCU control circuit is connected with the first range measurement conditioning circuit and the second range measurement conditioning circuit in a control mode and is used for controlling the display device when measuring current.
Generally, a modern measurement system has a single chip Microcomputer (MCU) or a computer as control display equipment, when measurement is carried out, the control equipment (MCU) reads data of two gears, and when the reading of a large current gear is too small, the reading of a small current gear is adopted. The reading of the high-current gear can be used when the reading of the high-current gear is large enough, that is, the current to be measured is large enough. Therefore, the present embodiment adopts the MCU control circuit, and the automatic seamless switching of the measurement range can be realized by reading the parameters of the MCU control circuit.
In one specific example: a diode D2 is also included, and a diode D2 is connected in anti-parallel with the diode D1 for measuring the alternating current.
The test method of the embodiment can be used for measuring direct current and also can be applied to measurement of alternating current.
In a specific example, the three-range current testing circuit further comprises a third-range measurement conditioning circuit, a diode D3, a diode D4 and a sampling resistor R3, the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel, the diode D3 and the diode D4 are reversely connected for measuring alternating current, the measuring end of the third-range measurement conditioning circuit is connected to two ends of the diode D3, the diode D4 and the sampling resistor R3, and finally the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel and then connected with the sampling resistor R2, the sampling resistor R1, a power supply and a load resistor RL in series to form a three-range current testing circuit.
The embodiment is easy to expand the measuring range and can realize three-measuring-range alternating current measurement.
In a specific example, the three-range current testing circuit further comprises a fourth-range measurement conditioning circuit, a diode D5 and a sampling resistor R4, wherein the diode D5 and the sampling resistor R4 are connected in parallel, a measuring end of the fourth-range measurement conditioning circuit is connected to two ends of the diode D5 and two ends of the sampling resistor R4, and finally the diode D5 and the sampling resistor R4 are connected in parallel and then connected with the sampling resistor R1, the sampling resistor R2, a power supply and a load resistor RL in series to form the three-range current testing circuit.
The embodiment is easy to expand the range, and can realize three-range direct current measurement.
Example 2
To achieve the above object, see fig. 3: the embodiment also provides a system for automatically switching the range measurement current, which comprises an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a diode D1, a sampling resistor R1, a sampling resistor R2, a power supply and a load resistor RL, wherein the measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1 and the sampling resistor R1, the measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D1 and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply and the load resistor RL to form a dual-range current test loop, and the MCU control circuit is connected with the first range measurement conditioning circuit and the second range measurement conditioning circuit in a control manner and used for controlling a display device during current measurement.
The beneficial effects of this embodiment are similar to the beneficial effects of the automatic switching range measurement current of embodiment 1 with respect to the prior art, and are not described herein again.
Example 3
In order to achieve the above object, this embodiment further provides a system for automatically switching a range measurement current, including an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a diode D1, a diode D2, a sampling resistor R1, a sampling resistor R2, a power supply, and a load resistor RL, where a measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1, the diode D2, and the sampling resistor R1, a measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D2 and the diode D1 are connected in parallel in an inverse direction for measuring an ac current, the diode D1, the diode D2, and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply, and the load resistor RL to form a dual-range current test loop, the MCU control circuit is connected to the first range measurement conditioning circuit and the second range measurement conditioning circuit in a control manner, for use in measuring current as a control display device.
The beneficial effects of this embodiment are similar to the beneficial effects of the automatic switching range measurement current of embodiment 1 with respect to the prior art, and are not described herein again.
Example 4
In order to achieve the above object, this embodiment further provides a system for automatically switching a range measurement current, including an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a third range measurement conditioning circuit, a diode D1, a diode D2, a diode D3, a diode D4, a sampling resistor R1, a sampling resistor R2, a sampling resistor R3, a power supply, and a load resistor RL, wherein a measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1, the diode D2, and the sampling resistor R1, a measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D2 is connected in reverse parallel with the diode D1 for measuring an ac current, the diode D3, the diode D4, and the sampling resistor R3 are connected in parallel, the diode D3 and the diode D4 are connected in reverse for measuring an ac current, the measuring end of the third range measuring and conditioning circuit is connected with two ends of a diode D3, a diode D4 and a sampling resistor R3, the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel and then connected with a sampling resistor R2, a sampling resistor R1, a power supply and a load resistor RL in series to form a three-range current testing loop, and the MCU control circuit is connected with the first range measuring and conditioning circuit, the second range measuring and conditioning circuit and the third range measuring and conditioning circuit in a control mode and used as a control display device when measuring current.
The beneficial effects of this embodiment are similar to the beneficial effects of the automatic switching range measurement current of embodiment 1 with respect to the prior art, and are not described herein again.
Example 5
In order to achieve the above object, this embodiment further provides a system for automatically switching a range measurement current, including an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a fourth range measurement conditioning circuit, a diode D1, a diode D5, a sampling resistor R1, a sampling resistor R2, a sampling resistor R4, a power supply, and a load resistor RL, where a measurement end of the first range measurement conditioning circuit is connected to two ends of the diode D1 and the sampling resistor R1, a measurement end of the second range measurement conditioning circuit is connected to two ends of the sampling resistor R2, the diode D1 is connected in parallel with the sampling resistor R1, a measurement end of the fourth range measurement conditioning circuit is connected to two ends of the diode D5 and the sampling resistor R4, the diode D5 and the sampling resistor R4 are connected in parallel, and then connected to the sampling resistor R1, the sampling resistor R2, the power supply, and the load resistor RL are connected in series to form a three-range current test loop, the MCU control circuit is in control connection with the first range measurement conditioning circuit, the second range measurement conditioning circuit and the fourth range measurement conditioning circuit and is used as control display equipment when measuring current.
The beneficial effects of this embodiment are similar to the beneficial effects of the automatic switching range measurement current of embodiment 1 with respect to the prior art, and are not described herein again.
Specifically, the method comprises the following steps: the forward conducting voltage of the diodes D1, D2, D3 and D4 is about 0.6V, and when the forward voltage is 0.1V, the forward current is 60 nA.
In summary, the basic principle of the expansion of the embodiments 3, 4, and 5 is consistent with the foregoing analysis and description (embodiment 1), only a diode with a proper conduction current needs to be selected according to the design range, and the value of the sampling resistor of the design range needs to be simply calculated and selected, that is, the test voltage signal can be conveniently and accurately obtained within the design range, and the leakage current passing through the diode can be ignored within the range. The simple calculation can be easily completed by electronic related engineering personnel. Compared with the existing method for measuring current by manual and automatic gear shifting, the method has the following advantages: the circuit is simple, the cost is low, and the calculation design is easy; the measurement reading in the range switching process and the current passing through the load equipment are in seamless connection, and the influence on the work of the load equipment is extremely small; the load current dynamic change measuring device is very suitable for continuous and accurate measurement of load current dynamic change, and the current values at the large end and the small end can easily guarantee the measurement accuracy no matter how violent the current change is.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A method for automatically switching range measurement current is characterized in that: the method comprises the following steps:
debugging a first measuring range measuring and conditioning circuit and a second measuring range measuring and conditioning circuit;
connecting the measuring end of the first range measurement conditioning circuit to two ends of a diode D1 and a sampling resistor R1;
connecting the measuring end of the second measuring range testing conditioning circuit with two ends of a sampling resistor R2;
finally, the diode D1 and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply and the load resistor RL to form a double-range current test loop.
2. The method of automatically switching span measurement current of claim 1 wherein: the MCU control circuit is connected with the first range measurement conditioning circuit and the second range measurement conditioning circuit in a control mode and is used for controlling the display device when measuring current.
3. The method of automatically switching span measurement current of claim 1 wherein: a diode D2 is also included, and a diode D2 is connected in anti-parallel with the diode D1 for measuring the alternating current.
4. The method of automatically switching span measurement current of claim 3 wherein: the three-range current testing circuit further comprises a third-range measuring and conditioning circuit, a diode D3, a diode D4 and a sampling resistor R3, the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel, the diode D3 and the diode D4 are connected in reverse to be used for measuring alternating current, the measuring end of the third-range measuring and conditioning circuit is connected to two ends of the diode D3, the diode D4 and the sampling resistor R3, and finally the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel and then connected with the sampling resistor R2, the sampling resistor R1, a power supply and a load resistor RL in series to form a three-range current testing loop.
5. The method of automatically switching span measurement current of claim 1 wherein: the three-range current testing circuit further comprises a fourth-range measuring and conditioning circuit, a diode D5 and a sampling resistor R4, the diode D5 and the sampling resistor R4 are connected in parallel, the measuring end of the fourth-range measuring and conditioning circuit is connected to the two ends of the diode D5 and the two ends of the sampling resistor R4, and finally the diode D5 and the sampling resistor R4 are connected in parallel and then connected with the sampling resistor R1, the sampling resistor R2, a power supply and a load resistor RL in series to form a three-range current testing circuit.
6. A system for automatically switching range measurement current is characterized in that: the device comprises an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a diode D1, a sampling resistor R1, a sampling resistor R2, a power supply and a load resistor RL, wherein the measurement end of the first range measurement conditioning circuit is connected with the two ends of the diode D1 and the sampling resistor R1, the measurement end of the second range measurement conditioning circuit is connected with the two ends of the sampling resistor R2, the diode D1 and the sampling resistor R1 are connected in parallel and then connected in series with the sampling resistor R2, the power supply and the load resistor RL to form a double-range current test loop, and the MCU control circuit is in control connection with the first range measurement conditioning circuit and the second range measurement conditioning circuit and is used as a control display device when measuring current.
7. A system for automatically switching range measurement current is characterized in that: comprises an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a diode D1, a diode D2, a sampling resistor R1, a sampling resistor R2, a power supply and a load resistor RL, the measuring end of the first range measurement conditioning circuit is connected to two ends of the diode D1, the diode D2 and the sampling resistor R1, the measuring end of the second measuring range measuring and conditioning circuit is connected with two ends of a sampling resistor R2, the diode D2 and the diode D1 are connected in reverse parallel for measuring alternating current, the diode D1, the diode D2 and the sampling resistor R1 are connected in parallel and then are connected in series with the sampling resistor R2, the power supply and the load resistor RL to form a double-range current test loop, the MCU control circuit is in control connection with the first range measurement conditioning circuit and the second range measurement conditioning circuit and is used as control display equipment when measuring current.
8. A system for automatically switching range measurement current is characterized in that: the device comprises an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a third range measurement conditioning circuit, a diode D1, a diode D2, a diode D3, a diode D4, a sampling resistor R1, a sampling resistor R2, a sampling resistor R3, a power supply and a load resistor RL, wherein the measurement end of the first range measurement conditioning circuit is connected with two ends of the diode D1, the diode D2 and the sampling resistor R1, the measurement end of the second range measurement conditioning circuit is connected with two ends of the sampling resistor R2, the diode D2 and the diode D1 are connected in parallel in an inverse direction for measuring alternating current, the diode D3, the diode D4 and the sampling resistor R3 are connected in parallel in a parallel direction, the diode D3 and the diode D4 are connected in the inverse direction for measuring alternating current, and the measurement end of the third range measurement conditioning circuit is connected with the diode D3, the diode 539D 2, the diode D4, The two ends of the sampling resistor R3 are connected in parallel with the diode D3, the diode D4 and the sampling resistor R3, and then connected with the sampling resistor R2, the sampling resistor R1, the power supply and the load resistor RL to form a three-range current test loop in series, and the MCU control circuit is in control connection with the first range measurement conditioning circuit, the second range measurement conditioning circuit and the third range measurement conditioning circuit and is used as a control display device when measuring current.
9. A system for automatically switching range measurement current is characterized in that: the device comprises an MCU control circuit, a first range measurement conditioning circuit, a second range measurement conditioning circuit, a fourth range measurement conditioning circuit, a diode D1, a diode D5, a sampling resistor R1, a sampling resistor R2, a sampling resistor R4, a power supply and a load resistor RL, wherein the measurement end of the first range measurement conditioning circuit is connected with two ends of a diode D1 and a sampling resistor R1, the measurement end of the second range measurement conditioning circuit is connected with two ends of a sampling resistor R2, the diode D1 is connected with the sampling resistor R1 in parallel, the measurement end of the fourth range measurement conditioning circuit is connected with two ends of a diode D5 and a sampling resistor R4, the diode D5 and the sampling resistor R4 are connected with the sampling resistor R1, the sampling resistor R2, the power supply and the load resistor RL in series to form a three-range current test loop, and the MCU control circuit is connected with the first range measurement conditioning circuit, the second range measurement conditioning circuit, the sampling, The second range measurement conditioning circuit and the fourth range measurement conditioning circuit are connected in a control mode and used for being used as control display equipment when measuring current.
10. The system for automatically switching span measurement current according to any of claims 6-9, wherein: the forward conduction voltage of the diodes D1, D2, D3 and D4 is 0.6V, and when the forward voltage is 0.1V, the forward current is 60 nA.
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| CN202011415636.4A CN112630517A (en) | 2020-12-03 | 2020-12-03 | Method and system for automatically switching range measurement current |
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| CN202011415636.4A CN112630517A (en) | 2020-12-03 | 2020-12-03 | Method and system for automatically switching range measurement current |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114167112A (en) * | 2021-12-16 | 2022-03-11 | 青岛东软载波智能电子有限公司 | High-precision wide-range low-differential-voltage current measuring circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114167112A (en) * | 2021-12-16 | 2022-03-11 | 青岛东软载波智能电子有限公司 | High-precision wide-range low-differential-voltage current measuring circuit |
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