CN204854855U - Air mass flow meter foil gage temperature compensation circuit of adjustable sampled value - Google Patents
Air mass flow meter foil gage temperature compensation circuit of adjustable sampled value Download PDFInfo
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- CN204854855U CN204854855U CN201520327509.7U CN201520327509U CN204854855U CN 204854855 U CN204854855 U CN 204854855U CN 201520327509 U CN201520327509 U CN 201520327509U CN 204854855 U CN204854855 U CN 204854855U
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Abstract
The utility model discloses an air mass flow meter foil gage temperature compensation circuit of adjustable sampled value, including penetrating along with ware UI, penetrate along with ware UI's input 1 and output between 3 and met electric capacity C, and penetrate and be connected with transistor Q's base through resistance R2 along with ware UI output 3, the last sampling circuit who still is provided with measuring resistance work piece R1 voltage of bridge circuit, sampling circuit includes potentiometre W1 and data collection point, potentiometre W1's a stiff end is connected with resistance work piece R1, and potentiometre W1's another stiff end and ground connection, data collection point is potentiometre W1's adjustable end, adopt the design mode of adjustable adoption voltage, a sampled value that forms is variable, do benefit to the air mass flow meter foil gage temperature compensation circuit that the circuit performance was adjusted, realize temperature compensating through negative temperature coefficient thermistor W3 to the foil gage, negative temperature coefficient thermistor W3's resistance is great, the error can effectually reduce to test.
Description
Technical field
The utility model relates to temperature compensation field, specifically, is a kind of air flowmeter foil gauge temperature-compensation circuit of adjustable sampled value.
Background technology
Foil gauge carries out by the change of measuring resistance a kind of element of measuring, can be used as sensor and act on working equipment, have the functions such as the pressure of test job equipment, temperature.Example is counted with the air mass flow of automobile, in its operational process, the resistance value of foil gauge is very large by the impact of temperature, be located at the foil gauge in air flow channel, flow through except the steady change of generation except experiencing air, the electric current flowing through foil gauge also makes its temperature change, and causes the relative change of resistance, produces false strain.For eliminating the temperature error of foil gauge, certain compensation method must be taked to compensate.In prior art, identical two foil gauges of usual employing or platinum resistance, one as active gage, use as compensating for one, because compensating plate resistance is low, slight precision change can cause the significantly change of result, larger to the influential effect compensated, thus cause the bigger error of test result, meanwhile, compensating plate is under open circuit conditions, big current is also easy to cause burning by active gage, because sample circuit adopts fixed resistance design, make sampled value be tending towards fixing, be unfavorable for the adjustment of circuit performance.
Utility model content
The purpose of this utility model is the air flowmeter foil gauge temperature-compensation circuit providing a kind of adjustable sampled value, adopt the Design Mode of adjustable employing voltage, a kind of sampled value formed is variable, be beneficial to the air flowmeter foil gauge temperature-compensation circuit that circuit performance regulates, by negative tempperature coefficient thermistor W3, temperature compensation is realized to foil gauge, the resistance of negative tempperature coefficient thermistor W3 is comparatively large, effectively can reduce test error.
The utility model is achieved through the following technical solutions: a kind of air flowmeter foil gauge temperature-compensation circuit of adjustable sampled value, comprise emitter follower UI, be connected to electric capacity C between the input end 1 of described emitter follower UI and output terminal 3, and emitter follower UI output terminal 3 is connected with the base stage of transistor Q by resistance R2, be connected to resistance R4 between the collector of described transistor Q and emitter, and the emitter of transistor Q is connected with bridge circuit; Described bridge circuit is primarily of foil gauge and compensating element, composition, described foil gauge is the resistance performance sheet R1 be located in runner, and resistance performance sheet R1 is connected with the emitter of transistor Q, described compensating element, is negative tempperature coefficient thermistor W3, and negative tempperature coefficient thermistor W3 connects a stiff end of potentiometer W2 by resistance R8, another stiff end of potentiometer W2 is connected with the emitter of transistor Q; The input end 1 of described emitter follower UI is connected on the connected node that resistance R8 is connected with potentiometer W2, and the input end 2 of emitter follower UI is connected on resistance performance sheet R1, the resistance of described negative tempperature coefficient thermistor W3 is greater than the resistance of resistance performance sheet R1, and described negative tempperature coefficient thermistor W3 is also parallel with resistance R3; Described bridge circuit is also provided with the sample circuit of measuring resistance active gage R1 voltage, described sample circuit comprises potentiometer W1 and data collection point, a stiff end of described potentiometer W1 is connected with resistance performance sheet R1, and another stiff end of potentiometer W1 is connected with ground wire, described data collection point is the adjustable end of potentiometer W1.
Further, for better realizing the utility model, also comprise resistance R5, resistance R6 and resistance R7, described resistance R5 is in parallel with resistance R6, and one end is connected with resistance performance sheet R1, and the other end connects with ground wire; Described resistance performance sheet R1 connects with resistance R7.
Further, for better realizing the utility model, the adjustable end setting position resistance met between adjustable end and ground wire of described potentiometer W1 is 1/10th of the total resistance of potentiometer W1.
The utility model compared with prior art, has the following advantages and beneficial effect:
The utility model adopts the Design Mode of adjustable employing voltage, a kind of sampled value formed is variable, be beneficial to the air flowmeter foil gauge temperature-compensation circuit that circuit performance regulates, by negative tempperature coefficient thermistor W3, temperature compensation is realized to foil gauge, the resistance of negative tempperature coefficient thermistor W3 is comparatively large, effectively can reduce test error.
The utility model adopts the negative tempperature coefficient thermistor W3 that resistance value is large, as the compensating element, of foil gauge, in the bridge circuit of its composition, the temperature variation that resistance performance sheet causes because of electric current can not only be eliminated, play the effect of temperature compensation, the error of measurement result can also be reduced, improve the accuracy and accuracy of measuring.
The utility model is also parallel with resistance R3 on compensating element, its role is to: when open circuit appears in compensating element, and resistance R3 can prevent from occurring big current in resistance performance sheet R1, effectively avoids resistance performance sheet R1 and is occurred by the situation of burning.
The utility model structure is simple, and the sampling resistance value ratio of potentiometer W1 is set to 9:1, further enhances the stability of circuit structure.
Accompanying drawing explanation
Fig. 1 is electrical block diagram of the present utility model.
Embodiment
Below in conjunction with embodiment, the utility model is described in further detail, but embodiment of the present utility model is not limited thereto.
Embodiment:
Be tending towards fixing for avoiding sampled value, be unfavorable for the adjustment of circuit performance, the air flowmeter foil gauge temperature-compensation circuit of a kind of adjustable sampled value of special design, adopt the Design Mode of adjustable employing voltage, a kind of sampled value formed is variable, be beneficial to the air flowmeter foil gauge temperature-compensation circuit that circuit performance regulates, by negative tempperature coefficient thermistor W3, temperature compensation is realized to foil gauge, the resistance of negative tempperature coefficient thermistor W3 is larger, effectively can reduce test error, as shown in Figure 1, be designed to following structure: comprise emitter follower UI, be connected to electric capacity C between the input end 1 of described emitter follower UI and output terminal 3, and emitter follower UI output terminal 3 is connected with the base stage of transistor Q by resistance R2, be connected to resistance R4 between the collector of described transistor Q and emitter, and the emitter of transistor Q is connected with bridge circuit, described bridge circuit is primarily of foil gauge and compensating element, composition, described foil gauge is the resistance performance sheet R1 be located in runner, and resistance performance sheet R1 is connected with the emitter of transistor Q, described compensating element, is negative tempperature coefficient thermistor W3, and negative tempperature coefficient thermistor W3 connects a stiff end of potentiometer W2 by resistance R8, another stiff end of potentiometer W2 is connected with the emitter of transistor Q, the input end 1 of described emitter follower UI is connected on the connected node that resistance R8 is connected with potentiometer W2, and the input end 2 of emitter follower UI is connected on resistance performance sheet R1, the resistance of described negative tempperature coefficient thermistor W3 is greater than the resistance of resistance performance sheet R1, and described negative tempperature coefficient thermistor W3 is also parallel with resistance R3, described bridge circuit is also provided with the sample circuit of measuring resistance active gage R1 voltage, described sample circuit comprises potentiometer W1 and data collection point, a stiff end of described potentiometer W1 is connected with resistance performance sheet R1, and another stiff end of potentiometer W1 is connected with ground wire, described data collection point is the adjustable end of potentiometer W1.
Further, for better realizing the utility model, also comprise resistance R5, resistance R6 and resistance R7, described resistance R5 is in parallel with resistance R6, and one end is connected with resistance performance sheet R1, and the other end connects with ground wire; Described resistance performance sheet R1 connects with resistance R7.
Further, for better realizing the utility model, the adjustable end setting position resistance met between adjustable end and ground wire of described potentiometer W1 is 1/10th of the total resistance of potentiometer W1.
In the prior art, compensating element, (as: foil gauge, platinum resistance) resistance often very little, therefore, very little deviation also can be exaggerated in circuit, cause the bigger than normal of test result error, and the utility model is for overcoming the problems referred to above, adopt negative tempperature coefficient thermistor W3 as compensating element, negative tempperature coefficient thermistor W3 is made by the very large semiconductor material of negative temperature coefficient or components and parts, when temperature is low, its resistance value is higher, along with the rising of temperature, resistance value exponentially relation reduces, in its circuit structure, there is larger resistance in negative tempperature coefficient thermistor W3, effectively can reduce the error of measurement result, there is the accuracy improving and measure, the advantages such as sensitivity.
The utility model adopts Bridge circuit compensation method to carry out temperature compensation to foil gauge, its principle is: in the course of work of resistance performance sheet R1, the electric current flowing through it can make its temperature change, its resistance also can variation with temperature and changing, in addition, because the temperature variation of air in runner is different with the linear expansion coefficient of resistance performance sheet R1 material, therefore, the resistance of resistance performance sheet R1 also can change, wherein, electric current is outwardness by the resistance change caused, the effect of bridge circuit is then: utilize the equilibrium response of electric bridge to eliminate by the resistance variations of electric current by causing, in its course of work, the resistance variations of resistance performance sheet R1 comprises two parts, a part is owing to straining the resistance variations caused, another part is due to the resistance variations of electric current by causing, in its circuit structure, resistance performance sheet R1 and negative tempperature coefficient thermistor W3 is connected respectively on an arm of electric bridge, during bridge voltage balance, the electric current of resistance performance sheet R1 makes its temperature remained constant, and the electric current of supply negative tempperature coefficient thermistor W3 makes the difference of both temperature keep constant.The size of current increase, depends on and the degree that foil gauge is cooled namely depends on the air capacity flowing through flowmeter.
When air flows through negative tempperature coefficient thermistor W3 and resistance performance sheet R1, both resistance is cooled, the temperature of resistance performance sheet R1 reduces, resistance reduces, bridge voltage will out of trim, and in order to keep bridge balance, bridge diagram will increase the electric current of supply resistance performance sheet R1, electric current on thermo-compensator is corresponding increase also, keeps constant make its temperature remained constant with the difference of the temperature of the temperature and negative tempperature coefficient thermistor W3 that ensure resistance performance sheet R1.When bridge current increases, the voltage on potentiometer W1 will raise, and is sampled by data collection point, thus the change of air mass flow is converted to the change of signal voltage.Because resistance is linear element, therefore on potentiometer W1, signal voltage also linearly changes with the change of air mass flow, and for improving the performance of whole supplementary circuitry, can resistance value ratio as required between regulator potentiometer, its optimal effectiveness is the adjustable end setting position resistance met between adjustable end and ground wire of potentiometer W1 is 1/10th of the total resistance of potentiometer W1, in actual application, signal voltage can be inputted ECU (Electrical Control Unit) ECU, just according to the height of signal voltage, the size of air mass flow can be calculated by ECU.
When open circuit appears in compensating element, resistance R3 can prevent from occurring big current in resistance performance sheet R1, effectively avoids resistance performance sheet R1 and is occurred by the situation of burning.
The utility model structure is simple, adopt the large negative tempperature coefficient thermistor W3 of resistance value as the compensating element, of foil gauge, the error of measurement result can not only be reduced, improve accuracy and the accuracy of measurement, also there is the advantages such as circuit structure is stable, security performance is strong.
The above; it is only preferred embodiment of the present utility model; not do any pro forma restriction to the utility model, every any simple modification, equivalent variations done above embodiment according to technical spirit of the present utility model, all falls within protection domain of the present utility model.
Claims (3)
1. the air flowmeter foil gauge temperature-compensation circuit of an adjustable sampled value, it is characterized in that: comprise emitter follower UI, be connected to electric capacity C between the input end 1 of described emitter follower UI and output terminal 3, and emitter follower UI output terminal 3 is connected with the base stage of transistor Q by resistance R2, be connected to resistance R4 between the collector of described transistor Q and emitter, and the emitter of transistor Q is connected with bridge circuit; Described bridge circuit is primarily of foil gauge and compensating element, composition, described foil gauge is the resistance performance sheet R1 be located in runner, and resistance performance sheet R1 is connected with the emitter of transistor Q, described compensating element, is negative tempperature coefficient thermistor W3, and negative tempperature coefficient thermistor W3 connects a stiff end of potentiometer W2 by resistance R8, another stiff end of potentiometer W2 is connected with the emitter of transistor Q; The input end 1 of described emitter follower UI is connected on the connected node that resistance R8 is connected with potentiometer W2, and the input end 2 of emitter follower UI is connected on resistance performance sheet R1, the resistance of described negative tempperature coefficient thermistor W3 is greater than the resistance of resistance performance sheet R1, and described negative tempperature coefficient thermistor W3 is also parallel with resistance R3; Described bridge circuit is also provided with the sample circuit of measuring resistance active gage R1 voltage, described sample circuit comprises potentiometer W1 and data collection point, a stiff end of described potentiometer W1 is connected with resistance performance sheet R1, and another stiff end of potentiometer W1 is connected with ground wire, described data collection point is the adjustable end of potentiometer W1.
2. the air flowmeter foil gauge temperature-compensation circuit of a kind of adjustable sampled value according to claim 1, it is characterized in that: also comprise resistance R5, resistance R6 and resistance R7, described resistance R5 is in parallel with resistance R6, and one end is connected with resistance performance sheet R1, and the other end connects with ground wire; Described resistance performance sheet R1 connects with resistance R7.
3. the air flowmeter foil gauge temperature-compensation circuit of a kind of adjustable sampled value according to claim 1 and 2, is characterized in that: the adjustable end setting position resistance met between adjustable end and ground wire of described potentiometer W1 is 1/10th of the total resistance of potentiometer W1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520327509.7U CN204854855U (en) | 2015-05-20 | 2015-05-20 | Air mass flow meter foil gage temperature compensation circuit of adjustable sampled value |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520327509.7U CN204854855U (en) | 2015-05-20 | 2015-05-20 | Air mass flow meter foil gage temperature compensation circuit of adjustable sampled value |
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| CN204854855U true CN204854855U (en) | 2015-12-09 |
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| CN201520327509.7U Expired - Fee Related CN204854855U (en) | 2015-05-20 | 2015-05-20 | Air mass flow meter foil gage temperature compensation circuit of adjustable sampled value |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108036804A (en) * | 2018-01-08 | 2018-05-15 | 成都柔电云科科技有限公司 | A kind of device adjusted for resistance strain gage output |
| CN111586932A (en) * | 2019-02-15 | 2020-08-25 | 半导体元件工业有限责任公司 | Semiconductor device and method thereof |
| CN117824771A (en) * | 2024-03-06 | 2024-04-05 | 成都睿宝电子科技有限公司 | Automatic temperature compensation circuit and compensation method for thermal flowmeter |
| CN117824771B (en) * | 2024-03-06 | 2024-06-04 | 成都睿宝电子科技有限公司 | Automatic temperature compensation circuit and compensation method for thermal flowmeter |
-
2015
- 2015-05-20 CN CN201520327509.7U patent/CN204854855U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108036804A (en) * | 2018-01-08 | 2018-05-15 | 成都柔电云科科技有限公司 | A kind of device adjusted for resistance strain gage output |
| CN108036804B (en) * | 2018-01-08 | 2024-03-01 | 成都柔电云科科技有限公司 | Device for adjusting output of resistance strain gauge |
| CN111586932A (en) * | 2019-02-15 | 2020-08-25 | 半导体元件工业有限责任公司 | Semiconductor device and method thereof |
| CN111586932B (en) * | 2019-02-15 | 2023-12-12 | 半导体元件工业有限责任公司 | Semiconductor device and method thereof |
| CN117824771A (en) * | 2024-03-06 | 2024-04-05 | 成都睿宝电子科技有限公司 | Automatic temperature compensation circuit and compensation method for thermal flowmeter |
| CN117824771B (en) * | 2024-03-06 | 2024-06-04 | 成都睿宝电子科技有限公司 | Automatic temperature compensation circuit and compensation method for thermal flowmeter |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| 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: 20151209 Termination date: 20190520 |