CN214583317U - High-precision physical quantity measuring device - Google Patents
High-precision physical quantity measuring device Download PDFInfo
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- CN214583317U CN214583317U CN202120792930.0U CN202120792930U CN214583317U CN 214583317 U CN214583317 U CN 214583317U CN 202120792930 U CN202120792930 U CN 202120792930U CN 214583317 U CN214583317 U CN 214583317U
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- resistor
- constant current
- current driving
- physical quantity
- amplifier
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- Measurement Of Current Or Voltage (AREA)
Abstract
The utility model provides a high-precision physical quantity measuring device, which comprises a voltage reference unit, a constant current driving unit and a measuring unit; the output end of the voltage reference unit is connected with the input end of the constant current driving unit; the measuring unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and an amplifier, wherein two ends of a series circuit formed by connecting the first resistor and the second resistor in series are respectively connected with a first output end and a second output end of the constant current driving unit, two ends of a series circuit formed by connecting the third resistor and the fourth resistor in series are respectively connected with the first output end and the second output end of the constant current driving unit, a connecting point of the first resistor and the second resistor is connected with a forward input end of the amplifier, and a connecting point of the third resistor and the fourth resistor is connected with a reverse input end of the amplifier. The utility model discloses can the accurate measurement physical quantity that awaits measuring.
Description
Technical Field
The utility model belongs to the technical field of the physical quantity measurement, concretely relates to high accuracy physical quantity measuring device.
Background
A wheatstone bridge is a bridge circuit composed of four resistors, which are respectively called the legs of the bridge. The Wheatstone bridge is a detection circuit, changes of physical quantity are measured by measuring changes of resistance, and although the Wheatstone bridge is simple in structure, the Wheatstone bridge is high in accuracy and sensitivity and widely applied to scientific research and detection instruments. In practical use, three of the resistors are usually fixed, and the other resistor is replaced by a thermistor, a piezoresistor, a PT100 and the like, so that the bridge can be used for measuring the physical quantity.
Strain gauges, magneto-resistive elements, semiconductor pressure sensors, and the like often operate in a bridge manner, and driving methods thereof include constant voltage driving and constant current driving. For the bridge driving device, the accuracy is an important index for measuring the performance of the bridge driving device, and the source of improving the accuracy is improving the accuracy of the reference voltage. Therefore, the utility model provides a bipolar bridge drive arrangement of accurate low-voltage, with the help of zener diode AD 589's accurate reference voltage and the cooperation of other accurate modules, and then promote bridge drive arrangement's accuracy under the operational environment of low-voltage by a wide margin.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to prior art's weak point, provide a high accuracy physical quantity measuring device.
In order to solve the above technical problem, the present invention provides, in a first aspect, a high-precision physical quantity measuring device, including a voltage reference unit, a constant current driving unit, and a measuring unit; the output end of the voltage reference unit is connected with the input end of the constant current driving unit and is used for providing reference voltage input for the constant current driving unit; the measuring unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and an amplifier, wherein two ends of a series circuit formed by connecting the first resistor and the second resistor in series are respectively connected with a first output end and a second output end of the constant current driving unit, two ends of a series circuit formed by connecting the third resistor and the fourth resistor in series are respectively connected with the first output end and the second output end of the constant current driving unit, a connecting point of the first resistor and the second resistor is connected with a forward input end of the amplifier, and a connecting point of the third resistor and the fourth resistor is connected with a reverse input end of the amplifier; and the resistance value of any one of the first resistor, the second resistor, the third resistor and the fourth resistor is a resistor which regularly changes along with the change of the physical quantity to be measured, and the resistance values of the rest resistors are kept stable.
With reference to the first aspect, in a first possible implementation manner, the voltage reference unit includes a zener diode with a model number AD 589.
With reference to the first aspect, in a second possible implementation manner, the constant current driving unit includes an operational amplifier AD822 and several resistors with an error lower than 1%.
With reference to the first aspect, in a third possible implementation manner, the amplifier includes a low power consumption instrumentation amplifier AD 620.
Compared with the prior art, the beneficial effects of the utility model are that: can accurately measure the physical quantity to be measured.
Drawings
Fig. 1 shows a schematic diagram of a high-precision physical quantity measuring apparatus according to an embodiment of the present invention;
fig. 2 shows a circuit diagram of a high-precision physical quantity measuring device according to an embodiment of the present invention.
Detailed Description
In order to make those skilled in the art better understand the technical solutions in the present specification, the technical solutions in the embodiments of the present specification will be clearly and completely described below with reference to the drawings in the embodiments of the present specification, and it is obvious that the described embodiments are only a part of the embodiments of the present specification, and not all of the embodiments. All other embodiments obtained by a person skilled in the art based on the embodiments in the present specification without any inventive step should fall within the scope of protection of the present specification. And the drawings described are only schematic and are non-limiting.
In this context, for the sake of brevity, not all possible combinations of individual features in the various embodiments or examples are described. Therefore, the respective features in the respective embodiments or examples may be arbitrarily combined as long as there is no contradiction between the combinations of the features, and all the possible combinations should be considered as the scope of the present specification.
The contents appearing in the present invention, which do not belong to the protection object of the present invention, are all for making the technical personnel in the field understand the present solution more easily, and should not be understood as seeking protection to these contents, and these contents all belong to the prior art.
In the description of the embodiments of the present invention, it should be further noted that unless explicitly stated or limited otherwise, the terms "disposed," "connected," and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be connected in wired or wireless communication; the two components can be directly connected or indirectly connected through an intermediate medium, and the two components can be communicated with each other; one or more of the above meanings may be referred to. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Fig. 1 shows a schematic diagram of a high-precision physical quantity measuring device according to an embodiment of the present invention. As shown in fig. 1, the high-precision physical quantity measuring device includes a voltage reference unit, a constant current driving unit, and a measuring unit; the output end of the voltage reference unit is connected with the input end of the constant current driving unit and is used for providing reference voltage input for the constant current driving unit; the measuring unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and an amplifier, wherein two ends of a series circuit formed by connecting the first resistor and the second resistor in series are respectively connected with a first output end and a second output end of the constant current driving unit, two ends of a series circuit formed by connecting the third resistor and the fourth resistor in series are respectively connected with the first output end and the second output end of the constant current driving unit, a connecting point of the first resistor and the second resistor is connected with a forward input end of the amplifier, and a connecting point of the third resistor and the fourth resistor is connected with a reverse input end of the amplifier; and the resistance value of any one of the first resistor, the second resistor, the third resistor and the fourth resistor is a resistor which regularly changes along with the change of the physical quantity to be measured, and the resistance values of the rest resistors are kept stable.
The voltage reference unit may include a zener diode model AD 589.
The constant current driving unit may include an operational amplifier AD822 and several resistors with an error of less than 1%.
The amplifier may include a low power instrumentation amplifier AD 620.
Fig. 2 shows a circuit diagram of a high-precision physical quantity measuring device according to an embodiment of the present invention. As shown in fig. 2, the voltage reference unit is composed of a zener diode AD589 and a peripheral resistor. The voltage stabilizing diode AD589 is a double-pin, low-cost and temperature compensation type band-gap reference voltage source, can provide fixed 1.235V reference voltage by using 50 muA to 5.0mA input current, and greatly improves the accuracy of the device.
The constant current driving unit is composed of an operational amplifier AD822 and a peripheral resistor. The adopted resistors R4-R7 are all resistors with the error within 1 percent. Two operational amplifiers amplify and invert the reference voltage in turn, and then realize constant current driving of the measuring unit through the resistors R2 and R8. The upper and lower end voltages of the bridge are +/-4.5V, the accuracy is high, and the bridge can be used as a reference voltage input end of the ADC.
The measuring unit consists of a Wheatstone bridge, an instrument amplifier AD620 and a peripheral resistor. The resistance values of the three resistors of the Wheatstone bridge are fixed, and the remaining resistor is used as a sensor, so that the change to be measured can be accurately detected. The low-power consumption instrumentation amplifier AD620 has high CMRR, and can accurately amplify the detection signal, thereby obtaining stable output.
It should be understood that parts of the specification not set forth in detail are well within the prior art. The scope of the present invention is not limited to the above-described embodiments, and it is obvious that those skilled in the art can make various modifications and variations to the present invention without departing from the scope and spirit of the present invention. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
Claims (4)
1. A high-precision physical quantity measuring device is characterized in that: the device comprises a voltage reference unit, a constant current driving unit and a measuring unit; the output end of the voltage reference unit is connected with the input end of the constant current driving unit and is used for providing reference voltage input for the constant current driving unit; the measuring unit comprises a first resistor, a second resistor, a third resistor, a fourth resistor and an amplifier, wherein two ends of a series circuit formed by connecting the first resistor and the second resistor in series are respectively connected with a first output end and a second output end of the constant current driving unit, two ends of a series circuit formed by connecting the third resistor and the fourth resistor in series are respectively connected with the first output end and the second output end of the constant current driving unit, a connecting point of the first resistor and the second resistor is connected with a forward input end of the amplifier, and a connecting point of the third resistor and the fourth resistor is connected with a reverse input end of the amplifier; and the resistance value of any one of the first resistor, the second resistor, the third resistor and the fourth resistor is a resistor which regularly changes along with the change of the physical quantity to be measured, and the resistance values of the rest resistors are kept stable.
2. The high-precision physical quantity measuring apparatus according to claim 1, characterized in that: the voltage reference unit comprises a voltage stabilizing diode with the model number AD 589.
3. The high-precision physical quantity measuring apparatus according to claim 1, characterized in that: the constant current driving unit comprises an operational amplifier AD822 and a plurality of resistors with errors lower than 1%.
4. The high-precision physical quantity measuring apparatus according to claim 1, characterized in that: the amplifier comprises a low power consumption instrumentation amplifier AD 620.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120792930.0U CN214583317U (en) | 2021-04-19 | 2021-04-19 | High-precision physical quantity measuring device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120792930.0U CN214583317U (en) | 2021-04-19 | 2021-04-19 | High-precision physical quantity measuring device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214583317U true CN214583317U (en) | 2021-11-02 |
Family
ID=78360440
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120792930.0U Expired - Fee Related CN214583317U (en) | 2021-04-19 | 2021-04-19 | High-precision physical quantity measuring device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214583317U (en) |
-
2021
- 2021-04-19 CN CN202120792930.0U patent/CN214583317U/en not_active Expired - Fee Related
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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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20211102 |