CN111504486A - Constant current circuit for temperature measurement and circuit breaker mechanical characteristic monitoring device - Google Patents
Constant current circuit for temperature measurement and circuit breaker mechanical characteristic monitoring device Download PDFInfo
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- CN111504486A CN111504486A CN202010292057.9A CN202010292057A CN111504486A CN 111504486 A CN111504486 A CN 111504486A CN 202010292057 A CN202010292057 A CN 202010292057A CN 111504486 A CN111504486 A CN 111504486A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
- G01K7/021—Particular circuit arrangements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M13/00—Testing of machine parts
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
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Abstract
The invention provides a constant current circuit for temperature measurement and a circuit breaker mechanical characteristic monitoring device, wherein the output end of a first amplifying circuit of the constant current circuit for temperature measurement is connected with the input end of a second amplifying circuit through a second resistor, and the two ends of the first resistor are respectively connected with a reference voltage end and the input end of the second amplifying circuit; the output end of the second amplifying circuit is connected with the input end of the first amplifying circuit through a third resistor, one end of the thermocouple is grounded, and the other end of the thermocouple is connected with the input end of the first amplifying circuit. According to the invention, through the matching of the first amplifying circuit and the second amplifying circuit, a constant differential pressure irrelevant to voltage ripples and thermocouple resistance is generated between the output of the second amplifying circuit and the input of the first amplifying circuit, a constant current is generated by utilizing the differential pressure, the resistance of the thermocouple is calculated through the voltage generated on the thermocouple by the current, the current temperature is further calculated, the influence of external voltage fluctuation is avoided, and the accuracy of temperature measurement is improved.
Description
Technical Field
The invention relates to the field of monitoring of mechanical characteristics of circuit breakers, in particular to a constant current circuit for temperature measurement and a monitoring device for mechanical characteristics of a circuit breaker.
Background
With the rapid development of electric power industry and the rapid advance of electric power automation systems in China, the regular maintenance work of power supply equipment of the electric power system is not more and more suitable for the actual needs of electric power production. The online monitoring of the equipment state is gradually introduced into the field of power system production research.
The breaker is an important executive component of the power system, is a large-scale power device which is only second to a generator and a transformer, completes switching operation when the breaker is normally operated, and accesses the device or a line into a power grid or quits the operation to play a role in operation control; when equipment and a line have faults, the fault line can be quickly cut off, normal operation of a fault-free part is ensured, and the operation protection effect is achieved. However, the circuit breaker is also an important power device with the most frequent failure, maintenance and parameter measurement, and has a high failure rate in the operation process, which easily causes grid accidents and causes large economic loss, so that a very high requirement is provided for the reliability of the circuit breaker.
In the prior art, the reliability of the circuit breaker is detected by using a mechanical characteristic monitoring mode of the circuit breaker, and the temperature of the circuit breaker needs to be measured during the mechanical characteristic monitoring. Thermocouples are often used to measure the temperature. However, the measurement accuracy of the thermocouple is easily affected by voltage fluctuation, while the conventional resistance voltage division method is adopted to supply power to the thermocouple, and the voltage provided by the resistance voltage division method is not only low in accuracy, but also easily affected by external voltage fluctuation, so that the temperature measurement of the thermocouple is affected, and the temperature is difficult to accurately measure.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a constant current circuit for temperature measurement and a circuit breaker mechanical characteristic monitoring device.
In order to solve the above problems, the present invention adopts a technical solution as follows: the utility model provides a constant current circuit is used in temperature measurement, constant current circuit is used in circuit breaker mechanical characteristics monitoring for the temperature measurement, constant current circuit is used in the temperature measurement includes: the thermocouple comprises a first amplifying circuit, a second amplifying circuit, a first resistor, a second resistor, a third resistor and a thermocouple, wherein the resistance values of the first resistor and the second resistor are the same, the voltage of an output end of the first amplifying circuit is equal to that of an input end, the voltage of the output end of the second amplifying circuit is twice of that of the input end, and the currents of the input ends of the first amplifying circuit and the second amplifying circuit are zero; the output end of the first amplifying circuit is connected with the input end of the second amplifying circuit through a second resistor, and two ends of the first resistor are respectively connected with the reference voltage end and the input end of the second amplifying circuit; the output end of the second amplifying circuit is connected with the input end of the first amplifying circuit through the third resistor, one end of the thermocouple is grounded, and the other end of the thermocouple is connected with the input end of the first amplifying circuit.
Furthermore, the first amplifying circuit comprises a first operational amplifier, wherein the homodromous input end of the first operational amplifier is connected with the thermocouple, and the inverting input end and the output end of the first operational amplifier are connected with the second resistor.
Furthermore, the second amplifying circuit comprises a second operational amplifier, a fourth resistor and a fifth resistor, wherein the homodromous input end of the second operational amplifier is connected with the output end of the first amplifying resistor through the second resistor, the inverting input end of the second operational amplifier is grounded through the fourth resistor, and two ends of the fifth resistor are respectively connected with the inverting input end and the output end of the second operational amplifier.
Further, the resistance value of the fourth resistor is equal to the resistance value of the fifth resistor.
Further, the voltage of the reference voltage terminal is 2.5V.
Based on the same inventive concept, the invention also provides a circuit breaker mechanical characteristic monitoring device, which comprises: the device comprises a reference voltage generating chip, a constant current circuit for temperature measurement and an analog-to-digital converter; the reference voltage end of the reference voltage generating chip is connected with the constant current circuit for temperature measurement, and the reference voltage is input to the constant current circuit for temperature measurement through the reference voltage generating chip; the analog-to-digital converter is connected with a thermocouple in the constant current circuit for temperature measurement, and the voltage value of the thermocouple is obtained through the analog-to-digital converter; the constant current circuit for temperature measurement includes: the thermocouple comprises a first amplifying circuit, a second amplifying circuit, a first resistor, a second resistor, a third resistor and a thermocouple, wherein the resistance values of the first resistor and the second resistor are the same, the voltage of an output end of the first amplifying circuit is equal to that of an input end, the voltage of the output end of the second amplifying circuit is twice of that of the input end, and the currents of the input ends of the first amplifying circuit and the second amplifying circuit are zero; the output end of the first amplifying circuit is connected with the input end of the second amplifying circuit through a second resistor, and two ends of the first resistor are respectively connected with the reference voltage end and the input end of the second amplifying circuit; the output end of the second amplifying circuit is connected with the input end of the first amplifying circuit through the third resistor, one end of the thermocouple is grounded, and the other end of the thermocouple is connected with the input end of the first amplifying circuit.
Furthermore, the first amplifying circuit comprises a first operational amplifier, wherein the homodromous input end of the first operational amplifier is connected with the thermocouple, and the inverting input end and the output end of the first operational amplifier are connected with the second resistor.
Furthermore, the second amplifying circuit comprises a second operational amplifier, a fourth resistor and a fifth resistor, wherein the homodromous input end of the second operational amplifier is connected with the output end of the first amplifying resistor through the second resistor, the inverting input end of the second operational amplifier is grounded through the fourth resistor, and two ends of the fifth resistor are respectively connected with the inverting input end and the output end of the second operational amplifier.
Further, the resistance value of the fourth resistor is equal to the resistance value of the fifth resistor.
Further, the voltage of the reference voltage terminal is 2.5V.
Compared with the prior art, the invention has the beneficial effects that: through the cooperation of the first amplifying circuit and the second amplifying circuit, a constant differential pressure irrelevant to voltage ripples and thermocouple resistance is generated between the output of the second amplifying circuit and the input of the first amplifying circuit, a constant current is generated by utilizing the differential pressure, the resistance of the thermocouple is calculated through the voltage generated by the current on the thermocouple, the current temperature is calculated, the influence of external voltage fluctuation is avoided, and the accuracy of temperature measurement is improved.
Drawings
FIG. 1 is a circuit diagram of a constant current circuit for measuring temperature according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of another embodiment of a constant current circuit for measuring temperature according to the present invention;
fig. 3 is a structural diagram of an embodiment of a circuit breaker mechanical characteristic monitoring device according to the present invention.
In the figure: r1: a first resistor; r2, a second resistor; r3, third resistor; r4, fourth resistor; r5, fifth resistor; r6, thermocouple; u1, a first operational amplifier; u2, a second operational amplifier.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.
Referring to fig. 1-2, fig. 1 is a circuit diagram of a constant current circuit for temperature measurement according to an embodiment of the present invention; fig. 2 is a circuit diagram of another embodiment of the constant current circuit for temperature measurement according to the present invention. The constant current circuit for temperature measurement of the present invention will be described in detail with reference to fig. 1-2.
In this embodiment, the constant current circuit for temperature measurement is applied to monitoring the mechanical characteristics of the circuit breaker, and includes: the constant current circuit for temperature measurement includes: the circuit comprises a first amplifying circuit, a second amplifying circuit, a first resistor R1, a second resistor R2, a third resistor R3 and a thermocouple R6, wherein the resistance values of the first resistor R1 and the second resistor R2 are the same, the voltage of an output end of the first amplifying circuit is equal to that of an input end, the voltage of the output end of the second amplifying circuit is twice of that of the input end, and the currents of the input ends of the first amplifying circuit and the second amplifying circuit are zero; the output end of the first amplifying circuit is connected with the input end of the second amplifying circuit through a second resistor R2, and two ends of a first resistor R1 are respectively connected with the reference voltage end and the input end of the second amplifying circuit; the output end of the second amplifying circuit is connected with the input end of the first amplifying circuit through a third resistor R3, one end of the thermocouple R6 is grounded, and the other end of the thermocouple R6 is connected with the input end of the first amplifying circuit.
In other embodiments, the constant current for measuring temperature may also be used for measuring water temperature, furnace temperature, and other object temperatures, which is not limited herein.
In a specific embodiment, the first resistor R1 and the second resistor R2 both have a resistance of 20K Ω, and the third resistor R3 has a resistance of 2.5K Ω. In other embodiments, the resistances of the first resistor R1, the second resistor R2, and the third resistor R3 may be other values, and only the resistances of the first resistor R1 and the second resistor R2 are equal, which is not limited herein.
In this embodiment, the first amplifying circuit includes a first operational amplifier U1, the first operational amplifier U1 has a unidirectional input connected to the thermocouple R6, and an inverted input and an output connected to the second resistor R2.
In one specific embodiment, the first operational amplifier U1 is a voltage follower having a voltage at the non-inverting input equal to the voltage at the output.
In this embodiment, the second amplifying circuit includes a second operational amplifier U2, a fourth resistor R4, and a fifth resistor R5, wherein the inverting input terminal of the second operational amplifier U2 is connected to the output terminal of the first amplifying resistor through the second resistor R2, the inverting input terminal is connected to ground through the fourth resistor R4, and two ends of the fifth resistor R5 are respectively connected to the inverting input terminal and the output terminal of the second operational amplifier U2.
In this embodiment, the second operational amplifier U2 is a same-direction scaling circuit, and the voltage of the same-direction input terminal of the same-direction scaling circuit is half of the voltage of the output terminal.
In the present embodiment, the resistance of the fourth resistor R4 is equal to the resistance of the fifth resistor R5, and both are 20K Ω.
In this embodiment, the voltage of the reference voltage terminal is 2.5V.
According to the invention, the voltage difference on the third resistor R3 is ensured to be stabilized at a fixed value through feedback cooperation of the two operational amplifiers, and under the condition that the resistance value of the third resistor R3 is fixed, the current I is equal to the voltage U/the resistor R according to the ampere theorem, the voltage U and the resistor R are both fixed at present, namely, the current flowing through the third resistor R3 is constant. While the current flowing through the third resistor R3 continues to flow through the thermocouple R6, the current is independent of the change in resistance of the thermocouple R6. The circuit operating condition did not change due to the change in resistance of thermocouple R6. Therefore, the voltage of the thermocouple R6 is only related to the resistance value of the thermocouple R6, and the accuracy of temperature monitoring is improved.
The working principle of the constant current circuit for temperature measurement of the present invention will be further described below.
The reference voltage terminal of the reference voltage generating chip generates 2.5V, because the input impedance of the second operational amplifier U2 is very high, and is in the G ohm level, i.e. the current I5 is very small and can be regarded as 0. According to kirchhoff's current law, the sum of the currents at the Vx points in fig. 2 is 0. I.e. I1+ I2+ I5 is 0. I5 is 0, i.e. I1+ I2 is 0.
Because I1 ═ (Vo' -Vx)/R2; i2 ═ (Vref _2.5v-Vx) R1. And I1+ I2 ═ 0. It can be obtained (Vo' -Vx)/R2+ (Vref _2.5v-Vx) R1 ═ 0. Fig. 2 shows R1 ═ R2. Therefore, (Vo' -Vx) + (Vref _2.5v-Vx) ═ 0 can be obtained; the simplified value can be 2Vx-Vo ═ Vref _2.5 v.
The second operational amplifier U2 in fig. 2 is an in-phase proportional amplifier circuit, i.e., Vx' ═ (1+ R4/R3) Vx (1+20K/20K) Vx 2 Vx. The first operational amplifier U1 is a voltage follower, i.e., Vo' ═ Vo; that is, the voltage drop across resistor R5 is equal to Vx '-Vo — 2 Vx-Vo'. Further, (2 Vx-Vo')/R5 of the current in the third resistor R3 is 2.5V/2.5K is 1 mA. The input impedance of the first operational amplifier U1 is very high, and is in the G ohm level, that is, the input current I4 of the first operational amplifier U1 is very small, and can be regarded as 0 for processing.
Therefore, the current I6, I3, flowing through the thermocouple R6 is 1mA, and the current is generated by feedback cooperation of the operational amplifier U1 and U2, regardless of the resistance value of the thermocouple R6. And inputting Vo to an analog-to-digital converter connected with the constant current circuit for temperature measurement to realize analog-to-digital conversion, calculating the voltage of Uo, dividing the voltage by the current 1mA, calculating the current resistance of the thermocouple R6 in a reverse mode, and finally, reversely calculating the current temperature according to the resistance of R6.
Has the advantages that: the constant current circuit for temperature measurement generates a constant voltage difference irrelevant to voltage ripples and thermocouple resistance values between the output of the second amplifying circuit and the input of the first amplifying circuit through the matching of the first amplifying circuit and the second amplifying circuit, generates a constant current by utilizing the voltage difference, calculates the resistance value of the thermocouple through the voltage generated on the thermocouple by the current, further calculates the current temperature, avoids the influence of external voltage fluctuation and improves the accuracy of temperature measurement.
Based on the same inventive concept, the present invention further provides a circuit breaker mechanical characteristic monitoring apparatus, please refer to fig. 3, fig. 3 is a structural diagram of an embodiment of the circuit breaker mechanical characteristic monitoring apparatus of the present invention, and the circuit breaker mechanical characteristic monitoring apparatus of the present invention is specifically described with reference to fig. 3.
The circuit breaker mechanical characteristic monitoring device includes: the device comprises a reference voltage generating chip, a constant current circuit for temperature measurement and an analog-to-digital converter; the reference voltage end of the reference voltage generating chip is connected with the constant current circuit for temperature measurement, and the reference voltage is input into the constant current circuit for temperature measurement through the reference voltage generating chip; the analog-to-digital converter is connected with a thermocouple in the constant current circuit for temperature measurement, and the voltage value of the thermocouple is obtained through the analog-to-digital converter; the constant current circuit for temperature measurement includes: the thermocouple comprises a first amplifying circuit, a second amplifying circuit, a first resistor, a second resistor, a third resistor and a thermocouple, wherein the resistance values of the first resistor and the second resistor are the same, the voltage of an output end of the first amplifying circuit is equal to that of an input end, the voltage of an output end of the second amplifying circuit is twice of that of the input end, and the currents of the input ends of the first amplifying circuit and the second amplifying circuit are zero; the output end of the first amplifying circuit is connected with the input end of the second amplifying circuit through a second resistor, and two ends of the first resistor are respectively connected with the reference voltage end and the input end of the second amplifying circuit; the output end of the second amplifying circuit is connected with the input end of the first amplifying circuit through a third resistor, one end of the thermocouple is grounded, and the other end of the thermocouple is connected with the input end of the first amplifying circuit.
In other embodiments, the constant current for measuring temperature may also be used for measuring water temperature, furnace temperature, and other object temperatures, which is not limited herein.
In a specific embodiment, the first resistor and the second resistor have a resistance of 20K Ω, and the third resistor has a resistance of 2.5K Ω. In other embodiments, the resistances of the first resistor, the second resistor, and the third resistor may be other values, and only the resistances of the first resistor and the second resistor are equal, which is not limited herein.
In this embodiment, the first amplifying circuit includes a first operational amplifier, a same-direction input end of the first operational amplifier is connected to the thermocouple, and an opposite-direction input end and an output end of the first operational amplifier are connected to the second resistor.
In a specific embodiment, the first operational amplifier is a voltage follower, and the voltage of the same-direction input end of the voltage follower is equal to the voltage of the output end of the voltage follower.
In this embodiment, the second amplifying circuit includes a second operational amplifier, a fourth resistor, and a fifth resistor, wherein a non-inverting input terminal of the second operational amplifier is connected to an output terminal of the first amplifying resistor through the second resistor, an inverting input terminal of the second operational amplifier is grounded through the fourth resistor, and two ends of the fifth resistor are respectively connected to an inverting input terminal and an output terminal of the second operational amplifier.
In this embodiment, the second operational amplifier is a same-direction proportional amplifying circuit, and the voltage of the same-direction input end of the same-direction proportional amplifying circuit is half of the voltage of the output end.
In this embodiment, the resistance of the fourth resistor is equal to the resistance of the fifth resistor, and both are 20K Ω.
In this embodiment, the voltage of the reference voltage terminal is 2.5V.
According to the invention, the differential pressure on the third resistor is ensured to be stabilized at a fixed value through the feedback cooperation of the two operational amplifiers, and under the condition that the resistance value of the third resistor is fixed, the current I is equal to the voltage U/the resistor R according to the ampere theorem, the voltage U and the resistor R are both fixed at present, namely, the current flowing through the third resistor is constant. While the current flowing through the third resistor continues to flow through the thermocouple regardless of the change in the resistance of the thermocouple. The working state of the circuit is not changed due to the change of the resistance value of the thermocouple. Therefore, the voltage of the thermocouple is only related to the resistance value of the thermocouple, and the accuracy of temperature monitoring is improved.
The working principle of the constant current circuit for temperature measurement has been described in the above embodiments, and is not described herein.
Has the advantages that: according to the circuit breaker mechanical characteristic monitoring device, through the cooperation of the first amplifying circuit and the second amplifying circuit, a constant differential pressure irrelevant to voltage ripples and thermocouple resistance values is generated between the output of the second amplifying circuit and the input of the first amplifying circuit, a constant current is generated by utilizing the differential pressure, the resistance value of the thermocouple is calculated through the voltage generated on the thermocouple by the current, the current temperature is further calculated, the influence of external voltage fluctuation is avoided, and the accuracy of temperature measurement is improved.
The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.
Claims (10)
1. The constant current circuit for temperature measurement is applied to monitoring of mechanical characteristics of a circuit breaker, and comprises: the thermocouple comprises a first amplifying circuit, a second amplifying circuit, a first resistor, a second resistor, a third resistor and a thermocouple, wherein the resistance values of the first resistor and the second resistor are the same, the voltage of an output end of the first amplifying circuit is equal to that of an input end, the voltage of the output end of the second amplifying circuit is twice of that of the input end, and the currents of the input ends of the first amplifying circuit and the second amplifying circuit are zero;
the output end of the first amplifying circuit is connected with the input end of the second amplifying circuit through a second resistor, and two ends of the first resistor are respectively connected with the reference voltage end and the input end of the second amplifying circuit;
the output end of the second amplifying circuit is connected with the input end of the first amplifying circuit through the third resistor, one end of the thermocouple is grounded, and the other end of the thermocouple is connected with the input end of the first amplifying circuit.
2. The constant current circuit for temperature measurement according to claim 1, wherein the first amplifier circuit includes a first operational amplifier, a homodromous input terminal of the first operational amplifier is connected to the thermocouple, and a reverse input terminal and an output terminal thereof are connected to the second resistor.
3. The constant current circuit for temperature measurement according to claim 1, wherein the second amplification circuit includes a second operational amplifier, a fourth resistor, and a fifth resistor, a same-direction input terminal of the second operational amplifier is connected to an output terminal of the first amplification resistor through the second resistor, an inverted-phase input terminal of the second operational amplifier is grounded through the fourth resistor, and both ends of the fifth resistor are connected to an inverted-phase input terminal and an output terminal of the second operational amplifier, respectively.
4. The constant current circuit for temperature measurement according to claim 3, wherein a resistance value of the fourth resistor is equal to a resistance value of the fifth resistor.
5. The constant current circuit for temperature measurement according to claim 1, wherein a voltage of the reference voltage terminal is 2.5V.
6. A circuit breaker mechanical characteristic monitoring device, comprising: the device comprises a reference voltage generating chip, a constant current circuit for temperature measurement and an analog-to-digital converter;
the reference voltage end of the reference voltage generating chip is connected with the constant current circuit for temperature measurement, and the reference voltage is input to the constant current circuit for temperature measurement through the reference voltage generating chip;
the analog-to-digital converter is connected with a thermocouple in the constant current circuit for temperature measurement, and the voltage value of the thermocouple is obtained through the analog-to-digital converter;
the constant current circuit for temperature measurement includes: the thermocouple comprises a first amplifying circuit, a second amplifying circuit, a first resistor, a second resistor, a third resistor and a thermocouple, wherein the resistance values of the first resistor and the second resistor are the same, the voltage of an output end of the first amplifying circuit is equal to that of an input end, the voltage of the output end of the second amplifying circuit is twice of that of the input end, and the currents of the input ends of the first amplifying circuit and the second amplifying circuit are zero;
the output end of the first amplifying circuit is connected with the input end of the second amplifying circuit through a second resistor, and two ends of the first resistor are respectively connected with the reference voltage end and the input end of the second amplifying circuit;
the output end of the second amplifying circuit is connected with the input end of the first amplifying circuit through the third resistor, one end of the thermocouple is grounded, and the other end of the thermocouple is connected with the input end of the first amplifying circuit.
7. The circuit breaker mechanical characteristic monitoring device of claim 6, wherein the first amplifying circuit comprises a first operational amplifier, a same-direction input end of the first operational amplifier is connected with the thermocouple, and an opposite-direction input end and an output end of the first operational amplifier are connected with the second resistor.
8. The apparatus for monitoring mechanical characteristics of circuit breaker according to claim 6, wherein said second amplifying circuit comprises a second operational amplifier, a fourth resistor and a fifth resistor, wherein a same-direction input terminal of said second operational amplifier is connected to an output terminal of said first amplifying resistor through said second resistor, an inverted-direction input terminal of said second operational amplifier is connected to ground through said fourth resistor, and two terminals of said fifth resistor are connected to an inverted-direction input terminal and an output terminal of said second operational amplifier, respectively.
9. The circuit breaker mechanical characteristic monitoring device of claim 8, wherein the fourth resistor has a resistance equal to the fifth resistor.
10. The apparatus for monitoring the mechanical characteristics of a circuit breaker according to claim 6, wherein the voltage of said reference voltage terminal is 2.5V.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010292057.9A CN111504486A (en) | 2020-04-14 | 2020-04-14 | Constant current circuit for temperature measurement and circuit breaker mechanical characteristic monitoring device |
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| CN202010292057.9A CN111504486A (en) | 2020-04-14 | 2020-04-14 | Constant current circuit for temperature measurement and circuit breaker mechanical characteristic monitoring device |
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| CN111504486A true CN111504486A (en) | 2020-08-07 |
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