CN203037744U - Circuit for accurately measuring resistors - Google Patents
Circuit for accurately measuring resistors Download PDFInfo
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- CN203037744U CN203037744U CN 201220702719 CN201220702719U CN203037744U CN 203037744 U CN203037744 U CN 203037744U CN 201220702719 CN201220702719 CN 201220702719 CN 201220702719 U CN201220702719 U CN 201220702719U CN 203037744 U CN203037744 U CN 203037744U
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- resistance
- circuit
- operational amplifier
- received
- measured
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Abstract
The utility model relates to a circuit for accurately measuring resistors. The circuit provided by the utility model contains a resistance voltage conversion circuit (1), a microcontroller unit (2) and a display (3). A measured resistor is connected to the resistance voltage conversion circuit. Resistance is converted to voltage which is inputted to an analog-digital conversion input port of the microcontroller unit and converted to a digital quantity through analog-digital conversion in the microcontroller unit. After being processed, the digital quantity is sent to the display so as to display the measured resistance. The resistance voltage conversion circuit is formed as follows: one end of a resistor R1 is connected with a power supply Vcc and then is connected in series with R2 and R3; the other end of R3 is grounded; a centre tap of the resistor R3 passes through a resistor R4 and then is connected to an in-phase input end of an operational amplifier A1; one end of a resistor R5 is grounded and the other end of R5 is connected to an inverted input end of the operational amplifier A1; and one end of a measured resistor Rx is connected to the inverted input end of the operational amplifier A1 and the other end of Rx is connected to an output end of the operational amplifier A1.
Description
Technical field
The utility model relates to the accurate measurement of resistance.Be mainly used in the resistance measuring instrument instruments and meters and need carry out electronic circuit and the fields of measurement thereof that resistance is accurately measured.
Background technology
Resistance is one of basic electrical quantity, measures under the DC condition of being everlasting, and also measures under the interchange situation.Under the direct current situation, resistance R is by volt-ampere characteristic definition, i.e. R=U/I, and wherein U is the voltage at resistance two ends, I is the electric current that flows through resistance.Under the interchange situation, resistance R defines by power P, i.e. the quadratic power of R=P/I.By used measurement instrument, resistance measurement can be divided into bridge method, volt ampere meter method, genuine standard and ohmmeter method.Bridge method, volt ampere meter method, genuine standard be measuring resistance accurately, but the measuring method complexity is not easy to quick measured resistance value.The ohmmeter method is measuring resistance fast, but reading is non-linear, low precision.The accurately quick measured resistance value of the utility model.
Summary of the invention
The purpose of this utility model is to provide a kind of accurately circuit of quick measuring resistance.Measured resistance is received resistive voltage change-over circuit (1), resistance value is converted to the analog to digital conversion input port that voltage is input to micro controller unit (2), analog to digital conversion through micro controller unit inside is digital quantity, and digital quantity is delivered to display (3) after treatment and shown the resistance value that measures.Resistance R 1 upper end pin connects power Vcc, resistance R 1 lower end pin is received resistance R 2 upper end pins, resistance R 2 lower end pins are received resistance R 3 upper end pins, resistance R 3 lower end pin ground connection, the center tap pin of resistance R 2 is received resistance R 4 left end pins, resistance R 4 right-hand member pins are received "+" input end of operational amplifier A 1, resistance R 5 left end pin ground connection, resistance R 5 right-hand member pins are received "-" input end of operational amplifier A 1, measured resistance R x left end pin connects operational amplifier A 1 "-" input end, and measured resistance R x right-hand member pin is received the output terminal of operational amplifier A 1.Pass between measured resistance R x and input voltage Ui and the output voltage U o is: Uo=Ui (1+Rx/R5) obtains the relation between measured resistance R x and the output voltage U o: Rx=(Uo/Ui-1) R5.Measure the value of Uo, obtain the value of resistance.
The technical solution of the utility model is as described below:
A kind of circuit of accurate measuring resistance comprises resistive voltage change-over circuit (1), micro controller unit (2), display (3).Resistive voltage change-over circuit (1) is a circuit that the resistance linearity is converted to voltage.Pass between measured resistance R x and input voltage Ui and the output voltage U o is: Uo=Ui (1+Rx/R5).At reference voltage that is constituted by resistance R 1, resistance R 2, resistance R 3 series connection bleeder circuits of input termination of homophase input amplifying circuit, regulate resistance R 2, make that Ui is 2.44V, when the measured resistance R x of correspondence was 0, output voltage U o was exactly 2.44.Measured resistance R x equates that with gear resistance R 5 output voltage U o is 4.88V.Measured resistance exceeds measurement range greater than gear resistance R 5.
The circuit of described a kind of accurate measuring resistance comprises microprocessor controls unit (2).The microprocessor controls unit is control center with the microcontroller that inside contains 10 AD modular converters, the output of the AD input port connecting resistance voltage conversion circuit (1) of microcontroller, analog-to-digital conversion module with microcontroller inside carries out analog to digital conversion to voltage signal, and transformation result is delivered to liquid crystal display after treatment and shown.2.44V voltage is through being that value after 10 A/D conversions of reference voltage is 500 with 5V; 4.88V voltage is through being that value after 10 A/D conversions of reference voltage is 1000 with 5V.After comparing through calculating and with gear resistance, the AD transforming numerical obtains the value of measured resistance.
Description of drawings
The utility model is described in further detail below in conjunction with accompanying drawing:
Fig. 1 is the utility model circuit block diagram;
Fig. 2 is resistive voltage change-over circuit figure of the present utility model;
Marginal data: among Fig. 2, A1 is operational amplifier, and R1, R2, R3 are that divider resistance obtains reference voltage Ui, and R5 is gear resistance, the measured resistance of Rx.
Embodiment
A kind of principle of work of circuit of accurate measuring resistance:
Fig. 1 is a kind of structural drawing of circuit of accurate measuring resistance.Comprise resistive voltage change-over circuit (1), micro controller unit (2), display (3).Fig. 2 is the circuit diagram of resistive voltage change-over circuit (1), be that a homophase amplifies operational amplifier, the reference voltage that resistance R 1, resistance R 2, resistance R 3 constitute, regulate resistance R 2, make that Ui is 2.44V, the relation between output voltage and the measured resistance is: Uo=Ui (1+Rx/R5), and Ui is reference voltage, regulate resistance R 2 and change Ui, regulate zero point.Measure the resistance that Uo just can obtain measured resistance.
The circuit of described a kind of accurate measuring resistance comprises the micro controller unit (2) centered by inside contains the microcontroller of 10 AD modular converters, enter the AD module from the Uo of resistive voltage change-over circuit from the analog to digital conversion input end of microcontroller, voltage U o signal is carried out analog to digital conversion, obtain the numerical value between 500 to 1000, microcontroller deducts radix 500 backs with numerical value between 500 to 1000 and obtains data between 0 to 500.The data that obtain be multiply by 2 backs divided by 1000, multiply by the resistance of gear resistance R 5, obtain the resistance of measured resistance.
The circuit of described a kind of accurate measuring resistance comprises 5V and 8V power supply.5V changes reference voltage as AD, and 8V is as the power supply of operational amplifier A 1.
The above only is preferred embodiment of the present utility model, and all equalizations of doing according to the utility model claim change and modify, and all should belong to covering scope of the present utility model.
Claims (2)
1. the circuit of an accurate measuring resistance is characterized in that: comprise resistive voltage change-over circuit (1), micro controller unit (2), display (3); Measured resistance is received described resistive voltage change-over circuit (1), be the analog to digital conversion input port that magnitude of voltage is input to described micro controller unit (2) with the resistance value linear transformation, be digital quantity through the micro controller unit analog to digital conversion, digital quantity is delivered to described display (3) after treatment and is shown the resistance value of measuring.
2. the circuit of a kind of accurate measuring resistance according to claim 1, it is characterized in that: described resistive voltage change-over circuit (1) comprises: resistance R 1 upper end pin connects power Vcc, resistance R 1 lower end pin is received resistance R 2 upper end pins, resistance R 2 lower end pins are received resistance R 3 upper end pins, resistance R 3 lower end pin ground connection, the center tap pin of resistance R 2 is received resistance R 4 left end pins, resistance R 4 right-hand member pins are received "+" input end of operational amplifier A 1, resistance R 5 left end pin ground connection, resistance R 5 right-hand member pins are received "-" input end of operational amplifier A 1, measured resistance R x left end pin connects operational amplifier A 1 "-" input end, and measured resistance R x right-hand member pin is received the output terminal of operational amplifier A 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220702719 CN203037744U (en) | 2012-12-19 | 2012-12-19 | Circuit for accurately measuring resistors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220702719 CN203037744U (en) | 2012-12-19 | 2012-12-19 | Circuit for accurately measuring resistors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203037744U true CN203037744U (en) | 2013-07-03 |
Family
ID=48689855
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220702719 Expired - Fee Related CN203037744U (en) | 2012-12-19 | 2012-12-19 | Circuit for accurately measuring resistors |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203037744U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104535843A (en) * | 2015-01-14 | 2015-04-22 | 秦辉 | Intelligent direct current stabilized power supply internal resistance measuring device |
| CN110927465A (en) * | 2019-11-26 | 2020-03-27 | 深圳供电局有限公司 | Direct current resistance measuring circuit and device |
-
2012
- 2012-12-19 CN CN 201220702719 patent/CN203037744U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104535843A (en) * | 2015-01-14 | 2015-04-22 | 秦辉 | Intelligent direct current stabilized power supply internal resistance measuring device |
| CN110927465A (en) * | 2019-11-26 | 2020-03-27 | 深圳供电局有限公司 | Direct current resistance measuring circuit and device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| DD01 | Delivery of document by public notice |
Addressee: Li Guiping Document name: Notification to Pay the Fees |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130703 Termination date: 20131219 |