CN203688669U - Contact resistance detection circuit of thin-film switch - Google Patents
Contact resistance detection circuit of thin-film switch Download PDFInfo
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- CN203688669U CN203688669U CN201320892083.0U CN201320892083U CN203688669U CN 203688669 U CN203688669 U CN 203688669U CN 201320892083 U CN201320892083 U CN 201320892083U CN 203688669 U CN203688669 U CN 203688669U
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- resistance
- power supply
- film switch
- operational amplifier
- thin film
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Abstract
The utility model discloses a contact resistance detection circuit of a thin-film switch. The contact resistance detection circuit of the thin-film switch comprises a resistance bridge, an operational amplifier, an indicator and a power supply. The output end of the resistance bridge is connected with the operational amplifier and the indicator orderly, and the power supply supplies power to the resistance bridge, the operational amplifier and the indicator separately. The resistance bridge comprises a thin-film switch contact array, a first resistor, a second resistor and an adjustable resistor, and one end of the first resistor and one end of the second resistor are both connected with the power supply. The other end of the first resistor is connected with one end of the thin-film switch contact array and the inverting input end of the operational amplifier separately, the other end of the second resistor is connected with one end of the adjustable resistor and the non-inverting input end of the operational amplifier separately, and the other end of the thin-film switch contact array and the other end of the adjustable resistors are both connected with the earth. The contact resistance detection circuit of the thin-film switch of the utility model can detect without needing manpower to operate a multimeter, is fast in detection speed and high in detection efficiency, accuracy and reliability, and can be widely used in the electronic equipment detection field.
Description
Technical field
The utility model relates to electronic equipment detection field, especially a kind of thin film switch contact resistance testing circuit.
Background technology
Thin film switch structure is rigorous, good looking appearance, and good airproof performance, has the advantage such as moisture proof and long service life, is widely used in the fields such as instrument, Industry Control, Medical Devices, auto industry, intelligent toy and the household electrical appliance of telecommunications, electronic surveying.
Can the contact resistance size of thin film switch contact be often used to weigh thin film switch and normally work.At present, generally need professional to operate universal electric meter and complete the contact resistance detection of thin film switch contact, detection speed is slow, and detection efficiency is low and cannot avoid operating mistake and the personal error in universal electric meter process, and accuracy and reliability are not high.
Utility model content
In order to solve the problems of the technologies described above, the purpose of this utility model is: the thin film switch contact resistance that a kind of detection speed is fast, detection efficiency is high and accuracy is high testing circuit is provided.
The utility model solves the technical scheme that its technical matters adopts: a kind of thin film switch contact resistance testing circuit, comprise resistance bridge, operational amplifier, indicator and power supply, the output terminal of described resistance bridge passes through operational amplifier and then is connected with the input end of indicator, and described power supply is respectively resistance bridge, operational amplifier and indicator power supply; Described resistance bridge comprises thin film switch contact dot matrix, the first resistance, the second resistance and adjustable resistance, one end of one end of described the first resistance and the second resistance is all connected with power supply, and the other end of described the first resistance is connected with thin film switch contact one end of dot matrix and the inverting input of operational amplifier respectively; The other end of described the second resistance is connected with one end of adjustable resistance and the in-phase input end of operational amplifier respectively; The described thin film switch contact other end of dot matrix and the other end of adjustable resistance are all connected with the earth.
Further, between the inverting input of described operational amplifier and output terminal, be also provided with the 3rd resistance for adjusting operational amplifier reversal rate.
Further, described indicator comprises power supply access indicating member and contact conducting indicating member, one end of described power supply access indicating member is connected with power supply, the other end of described power supply access indicating member is connected with the earth, described power supply is also connected with contact conducting indicating member, and the input end of described contact conducting indicating member is also connected with the output terminal of operational amplifier.
Further, described power supply access indicating member comprises the 4th resistance and power supply access pilot lamp, and one end of described the 4th resistance is connected with power supply, and the other end of described the 4th resistance accesses pilot lamp by power supply and then is connected with the earth.
Further, described contact conducting indicating member comprises hummer, the 5th resistance, contact conducting pilot lamp, triode, the 6th resistance, diode, the 7th resistance, described power supply passes through hummer and then is connected with the collector of triode, and described power supply is also connected with contact conducting pilot lamp and then with the collector of triode by the 5th resistance successively; The anode of described diode is connected with the output terminal of operational amplifier, the negative electrode of described diode passes through the 6th resistance and then is connected with the base stage of triode, the base stage of described triode is also passed through the 7th resistance and then is connected the grounded emitter of described triode with the earth.
Further, described power supply access pilot lamp is green LED.
Further, described contact conducting pilot lamp is yellow light-emitting diode.
Further, described operational amplifier is LM741 operational amplifier.
The beneficial effects of the utility model are: the resistance bridge being made up of thin film switch contact dot matrix, the first resistance, the second resistance and adjustable resistance coordinates operational amplifier and indicator, detect thin film switch contact resistance without manual operation universal electric meter, detection speed is fast, detection efficiency is high, and accuracy and reliability high.
Brief description of the drawings
Below in conjunction with Figure of description and embodiment, the utility model is described in further detail.
Fig. 1 is the structured flowchart of a kind of thin film switch contact resistance of the utility model testing circuit.
Embodiment
With reference to Fig. 1, a kind of thin film switch contact resistance testing circuit, comprise resistance bridge, operational amplifier IC, indicator and power supply, the output terminal of described resistance bridge passes through operational amplifier IC and then is connected with the input end of indicator, and described power supply is respectively resistance bridge, operational amplifier IC and indicator power supply; Described resistance bridge comprises thin film switch contact dot matrix, the first resistance R 1, the second resistance R 2 and adjustable resistance R3, one end of one end of described the first resistance R 1 and the second resistance R 2 is all connected with power supply, and the other end of described the first resistance R 1 is connected with thin film switch contact one end of dot matrix and the inverting input of operational amplifier IC respectively; The other end of described the second resistance R 2 is connected with one end of adjustable resistance R3 and the in-phase input end of operational amplifier IC respectively; The described thin film switch contact other end of dot matrix and the other end of adjustable resistance R3 are all connected with the earth.
Wherein, resistance bridge, for the contact resistance of testing film switch contact.Operational amplifier, is high-gain list amplifier, for change the output state of oneself according to the output error voltage of resistance bridge.Indicator, for making the whether satisfactory acousto-optic hint of contact resistance according to the output state of operational amplifier.
With reference to Fig. 1, be further used as preferred embodiment, between the inverting input of described operational amplifier IC and output terminal, be also provided with the 3rd resistance R 4 for adjusting operational amplifier reversal rate.
With reference to Fig. 1, be further used as preferred embodiment, described indicator comprises power supply access indicating member and contact conducting indicating member, one end of described power supply access indicating member is connected with power supply, the other end of described power supply access indicating member is connected with the earth, described power supply is also connected with contact conducting indicating member, and described contact conducting indicating member is also connected with the output terminal of operational amplifier IC.
With reference to Fig. 1, be further used as preferred embodiment, described power supply access indicating member comprises the 4th resistance R 5 and power supply access pilot lamp VD3, and one end of described the 4th resistance R 5 is connected with power supply, and the other end of described the 4th resistance R 5 accesses pilot lamp VD3 by power supply and then is connected with the earth.
With reference to Fig. 1, be further used as preferred embodiment, described contact conducting indicating member comprises hummer HA, the 5th resistance R 6, contact conducting pilot lamp VD2, triode V1, the 6th resistance R 7, diode VD1, the 7th resistance R 8, described power supply passes through hummer HA and then is connected with the collector of triode V1, and described power supply is also connected with contact conducting pilot lamp VD2 and then with the collector of triode V1 by the 5th resistance R 6 successively; The anode of described diode VD1 is connected with the output terminal of operational amplifier IC, the negative electrode of described diode VD1 passes through the 6th resistance R 7 and then is connected with the base stage of triode V1, the base stage of described triode V1 is also passed through the 7th resistance R 8 and then is connected the grounded emitter of described triode V1 with the earth.
Wherein, hummer is the active piezoelectric buzzer of 5V, and working current is not more than 20mA.
Be further used as preferred embodiment, described power supply access pilot lamp VD3 is green LED.
Be further used as preferred embodiment, described contact conducting pilot lamp VD2 is yellow light-emitting diode.
Be further used as preferred embodiment, described operational amplifier IC is LM741 operational amplifier.
Below in conjunction with Figure of description and specific embodiment, the present invention is described in further detail.
With reference to Fig. 1, first embodiment of the invention:
Four arms of the contact resistance composition electric bridge of resistance R 1, R2, adjustable resistance R3 and thin film switch.Because R1 equals R2, according to electric resistance partial pressure relation, in the time that the contact resistance of thin film switch is greater than R3, resistance bridge is to the 2nd pin input noble potential of operational amplifier IC; In the time that the contact resistance of thin film switch is less than R3, electric bridge is to the 3rd pin input noble potential of operational amplifier IC.
Operational amplifier IC(LM741 or CA741) serve as comparer.In the time of in-phase input end (3 pin) input noble potential, output terminal (6 pin) is also exported noble potential; In the time of inverting input (2 pin) input noble potential, output terminal (6 pin) output electronegative potential.Therefore, in the time that the contact resistance of thin film switch contact is greater than R3, the 2nd pin input noble potential of IC, 6 pin output electronegative potentials; In the time that thin film switch contact resistance is less than R3, the 3rd pin input noble potential of IC, 6 pin output noble potentials.
When the 6th pin of IC is exported electronegative potential, can drive triode V1 cut-off, now contact conducting instruction diode VD2 and the equal no current of hummer HA flow through, and therefore indicate without acousto-optic; When the 6th pin of IC is exported noble potential, triode V1 saturation conduction, now conducting instruction diode VD2 and hummer HA all have electric current to flow through, and send acousto-optic indicator signal.
In sum, in the time that the contact resistance of thin film switch contact is less than R3, from the 3rd pin input noble potential of IC, amplifier IC exports noble potential, drives triode V1 saturated, and VD2 and HA all send indicator signal.Otherwise VD2 and HA all do not send indicator signal.Regulate the large I of R3 to change the contact resistance size that starts instruction.
Embodiment 2
As an example of R3=500 ohm example, to the present invention, the debug process before detection describes the present embodiment.
After circuit welding is errorless, access+5V direct supply, power supply access pilot lamp VD3 should light.Power turn-on switch S, contact conducting pilot lamp VD2 should not work, not ring of hummer HA.Between the 2nd pin of IC and the earth, access 500 Ohmages, regulate adjustable resistance R3 to make VD2 and HA just not occur acousto-optic instruction, then remove the resistance accessing between the 2nd pin and the earth, complete debugging, now, R3 resistance should be also 500 ohm of left and right.If the sound of hummer is less than normal, can suitably reduce the resistance of R7; If the brightness of VD2 is less than normal, can suitably reduce the resistance of R6; If the state turnover speed of IC is slow, one end that the resistance that can suitably increase R4 even connects IC the 2nd pin R4 is transferred to the 3rd pin.
Embodiment 3
The present embodiment describes use procedure of the present invention as an example of R3=500 ohm example.
First, access+5V direct supply, after power supply access pilot lamp VD3 lights, switch S switches on power.
The lead-in wire port of thin film switch is inserted to 11 pin sun mouthful sockets, note aiming at the separation that matrix goes between in length and breadth.
Press one by one each contact of thin film switch, if all there is acousto-optic instruction at every turn, illustrate that contact contact resistance meets the requirement that is less than 500 ohm; If there is not acousto-optic instruction, illustrate that the contact resistance of corresponding contacts is greater than 500 ohm, undesirable.
The present invention has following characteristics:
A. resistance bridge is applied to the contact resistance that detects thin film switch contact;
B. select the voltage comparator of operational amplifier composition to improve sensitivity and the reliability of detection;
C. adopt the qualification of sound and luminous dual mode prompting contact resistance;
D. use light safe acrylic board shell, panel layout is designed with and is beneficial to operation and observes, and with operation instructions.
Compared with prior art, the utlity model has following advantage:
(1). compared with the mode manually detecting with multimeter, greatly improved the detection speed of thin film switch contact contact resistance, and the contact of thin film switch is more, the efficiency of raising is also more;
(2). avoided mistake and personal error in operation universal electric meter process completely, accuracy and reliability are high;
(3). highly versatile, can be used for the detection of the dissimilar thin film switch of no more than 28 of contact;
(4). according to different needs, can arrive in tens Europe the qualified index of flexible contact resistance between hundreds of Europe.
More than that better enforcement of the present utility model is illustrated, but the utility model is created and is not limited to described embodiment, those of ordinary skill in the art also can make all equivalent variations or replacement under the prerequisite without prejudice to the utility model spirit, and the distortion that these are equal to or replacement are all included in the application's claim limited range.
Claims (8)
1. a thin film switch contact resistance testing circuit, it is characterized in that: comprise resistance bridge, operational amplifier (IC), indicator and power supply, the output terminal of described resistance bridge passes through operational amplifier (IC) and then is connected with the input end of indicator, and described power supply is respectively resistance bridge, operational amplifier (IC) and indicator power supply; Described resistance bridge comprises thin film switch contact dot matrix, the first resistance (R1), the second resistance (R2) and adjustable resistance (R3), one end of described the first resistance (R1) is all connected with power supply with one end of the second resistance (R2), and the other end of described the first resistance (R1) is connected with thin film switch contact one end of dot matrix and the inverting input of operational amplifier (IC) respectively; The other end of described the second resistance (R2) is connected with one end of adjustable resistance (R3) and the in-phase input end of operational amplifier (IC) respectively; The other end of described thin film switch contact dot matrix is all connected with the earth with the other end of adjustable resistance (R3).
2. a kind of thin film switch contact resistance testing circuit according to claim 1, is characterized in that: between the inverting input of described operational amplifier (IC) and output terminal, be also provided with the 3rd resistance (R4) for adjusting operational amplifier (IC) reversal rate.
3. a kind of thin film switch contact resistance testing circuit according to claim 1, it is characterized in that: described indicator comprises power supply access indicating member and contact conducting indicating member, one end of described power supply access indicating member is connected with power supply, the other end of described power supply access indicating member is connected with the earth, described power supply is also connected with contact conducting indicating member, and the input end of described contact conducting indicating member is also connected with the output terminal of operational amplifier (IC).
4. a kind of thin film switch contact resistance testing circuit according to claim 3, it is characterized in that: described power supply access indicating member comprises the 4th resistance (R5) and power supply access pilot lamp (VD3), one end of described the 4th resistance (R5) is connected with power supply, and the other end of described the 4th resistance (R5) is accessed pilot lamp (VD3) and then is connected with the earth by power supply.
5. a kind of thin film switch contact resistance testing circuit according to claim 3, it is characterized in that: described contact conducting indicating member comprises hummer (HA), the 5th resistance (R6), contact conducting pilot lamp (VD2), triode (V1), the 6th resistance (R7), diode (VD1), the 7th resistance (R8), described power supply passes through hummer (HA) and then is connected with the collector of triode (V1), and described power supply is also connected with contact conducting pilot lamp (VD2) and then with the collector of triode (V1) by the 5th resistance (R6) successively; The anode of described diode (VD1) is connected with the output terminal of operational amplifier (IC), the negative electrode of described diode (VD1) passes through the 6th resistance (R7) and then is connected with the base stage of triode (V1), the base stage of described triode (V1) is also passed through the 7th resistance (R8) and then is connected the grounded emitter of described triode (V1) with the earth.
6. a kind of thin film switch contact resistance testing circuit according to claim 4, is characterized in that: described power supply access pilot lamp (VD3) is green LED.
7. a kind of thin film switch contact resistance testing circuit according to claim 5, is characterized in that: described contact conducting pilot lamp (VD2) is yellow light-emitting diode.
8. according to a kind of thin film switch contact resistance testing circuit described in claim 1-7 any one, it is characterized in that: described operational amplifier (IC) is LM741 operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320892083.0U CN203688669U (en) | 2013-12-31 | 2013-12-31 | Contact resistance detection circuit of thin-film switch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320892083.0U CN203688669U (en) | 2013-12-31 | 2013-12-31 | Contact resistance detection circuit of thin-film switch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203688669U true CN203688669U (en) | 2014-07-02 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320892083.0U Expired - Fee Related CN203688669U (en) | 2013-12-31 | 2013-12-31 | Contact resistance detection circuit of thin-film switch |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203688669U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105510758A (en) * | 2015-11-27 | 2016-04-20 | 湖北三江航天红峰控制有限公司 | Device for low resistance conduction |
| CN113466563A (en) * | 2021-07-30 | 2021-10-01 | 深圳市汇创达科技股份有限公司 | Device for testing resistance of multi-path resistor |
-
2013
- 2013-12-31 CN CN201320892083.0U patent/CN203688669U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105510758A (en) * | 2015-11-27 | 2016-04-20 | 湖北三江航天红峰控制有限公司 | Device for low resistance conduction |
| CN113466563A (en) * | 2021-07-30 | 2021-10-01 | 深圳市汇创达科技股份有限公司 | Device for testing resistance of multi-path resistor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 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: 20140702 Termination date: 20211231 |