GB/T 15653-1995 Test methods for metal oxide semiconductor gas sensors
Some standard content:
National Standard of the People's Republic of China
Measuring methods for gas sensors of metal-oxide semiconductor1 Subject content and scope of application
GB/T 15653—1995
This standard specifies the basic principles of the performance parameter test methods of metal-oxide semiconductor gas sensors (hereinafter referred to as components), but does not specify the technical details of these methods in actual use. The test can be carried out in accordance with the provisions of the corresponding detailed specifications. This standard is applicable to the test of the performance parameters of metal-oxide semiconductor gas sensors, and other gas sensors can also be used as a reference. 2 Reference standards
GB2421 General basic environmental test rules for electrical and electronic products
GB3095 Atmospheric environment quality standards
GB1475 Terminology of sensitive components
3 Terminology, symbols
3.1 Terminology
The terms used in this standard shall be in accordance with the provisions of GB4475. 3.2 Symbols
The parameter symbols of this standard shall comply with the provisions of Appendix A (supplement) of this standard. 4 General requirements
4.1 Test box
a. The box material of the test box shall be selected from materials that do not react with the detection gas; b. The box volume shall ensure that the average volume occupied by each component is not less than 1L; c. The box shall be equipped with a liquid vaporization device, a temperature and humidity display device and a gas stirring pipe. 4.2 Test atmosphere
The requirements for clean air shall comply with the Class 2 ambient air standards specified in GB8095. When using calibration gas for detection, the concentration tolerance shall comply with the provisions of Table 1. Approved by the State Administration of Technical Supervision on July 24, 1995, and implemented on April 1, 1996
4.3 Power supply
Volume ratio concentration range
100~1000
>1 000
GB/T15653—1995
Allowable error
The error of the voltage (or current) of the regulated power supply (or regulated current supply) within the given value range shall not exceed 2%. 4.4 Test instrument
The error of the indicating voltmeter and ammeter (including range extension) shall not exceed 1%. A digital voltmeter with high input impedance shall be used to measure the output voltage on the load resistor. 4.5 Test environment conditions
Unless there are special conditions, the measurement of various parameters of the components shall be carried out under the standard atmospheric conditions specified in GB2421. Standard atmospheric conditions for the test
Temperature: 15~35
Relative humidity: 45%~75%,
Air pressure: 86~106 kPa.
Standard atmospheric conditions for arbitration test
Temperature: 25±1℃;
Relative humidity: 48%~52%,
Air pressure: 86~106 kPa.
4.6 Test environmental conditions allowable error
Ambient temperature: During the test, the ambient temperature should not change by more than 12°C Relative humidity: During the test, the relative humidity should not change by more than ±5%: Air pressure: During the test, the atmospheric pressure should not change by more than ±5%. General precautions
All the measurements of the numbers should be carried out under the specified working conditions; when testing a certain number of components continuously, the test time requirements must be specified; before the test, the length of time the components are kept under the test conditions should be specified; if the reading measured by doubling the time between the time when the component is powered on and the test changes within the specified error, it is considered that the component has reached the initial steady state:
If the reading measured by doubling the time between the time when the optical component is in a certain working state and the test changes within the specified error, it is considered that the component has reached the steady state.
5 Parameter test
5-1 Component resistance value in clean air (R.) 5-1. 1 Definition
The steady-state resistance value of the component in clean air under the specified working conditions. 5.1.2 Test circuit diagram
See Figure 1 for the test circuit diagram.
GB/T15653—1995
Air-cooled components
In the figure: G, is the steady power supply; P, P is the voltmeter, P is the ammeter, R, is the load resistor; P. is the voltmeter on the load resistor; V. is the test loop voltage; V. is the heating voltage; l. is the heating current. 5.1.3 Test steps
Adjust the heating voltage V (or current I) so that the reading of the voltmeter (or ammeter) is the specified value a
Adjust the test loop voltage V. so that the reading of the voltmeter is the specified value: bh.
Select the load resistance R. as the specified value:
Introduce clean air into the test box;
Read the output voltage steady-state value V. on the load resistor in the clean air on the digital voltmeter. 5. 1, 4 Calculate the steady-state resistance of the component in clean air, R. Where: R,
Steady-state resistance of the component in clean air, kn Test circuit voltage, V;
Steady-state value of the output voltage on the load resistor in clean air, V Load resistance, kn.
5. 1. 5 Specified conditions
Heating voltage (or heating current);
Test circuit voltage:
Load resistance,
Preheating time.
5.2 Resistance of the component in the test gas (Raz) 5.2.1 Definition
Steady-state resistance of the component in the test gas of specified concentration under specified working conditions. 5. 2. 2 Test system diagram
See Figure 1 for the test system diagram.
5.2.3 Test steps
GB/T 15653—1995
Perform according to the provisions of 5.1.3 a, b, c; prepare the test gas of the specified concentration according to the gas distribution method of volume ratio mixing method in Appendix B (Supplement); b.
c. Read the output voltage steady-state value Va on the load resistor in the test gas on the digital voltmeter: 5.2.4 Calculate
The steady-state resistance of the element in the test gas is; Where: Rt-
V.- V × rl
Steady-state resistance of the element in the test gas, ka, test circuit voltage, V
Output steady-state voltage on the load resistor in the test gas, V; load resistance, k.
5.2.5 Specified conditions
Same as the provisions of 5.1.5
Type and concentration of the test gas.
Note: When measuring the resistance in the interference gas, just change 5.2.3 b to "matching interference gas" and change the relevant parameter subscript dg to ig. 5.3 Heating power (Ph)
5.3.1 Definition
The product of the heating voltage and heating current of the component under the specified working conditions. 5.3.2 Test system diagram
The test system diagram is shown in Figure 1.
5.3. 3 Test steps
. Follow the provisions of 5.1.3 a;
b. Read the heating current I value (or heating voltage Vh value) on the heating current meter (or voltage meter). 5.3.4 Calculate the heating power as follows: PA = Vi × Ih Where: P - heating power, mw; V - heating voltage, V, I - heating current, mA. 5.3.5 Specified conditions Heating voltage (or heating current). 5.4 Sensitivity (S) 5.4.1 Definition The ratio of the steady-state resistance of the element in clean air to the steady-state resistance in the test gas of specified concentration under specified working conditions. 5.4.2 Test system diagram See Figure 1 for the test system diagram.
5.4.3 Test steps
Measure V according to the provisions of 5.1.3;
Measure Vaxl according to the provisions of 5.2.3
Calculate R and Rd according to formula (1) of 5.1.4 and formula (2) of 5.2.4 respectively.5.4.4 Calculate the sensitivity as
GB/T15653-1995
Where: S—-sensitivity:
R.—Steady-state resistance of the element in clean air, ko; R
R——Steady-state resistance of the element in the detection gas, k?. Note: When measuring P-type elements or detecting oxidizing gases, the side number form of formula (4) can be used. 5.4.5 Specified conditions
Same as the provisions of 5.2.5.
5.5 Gas Resolution (D)
5. 5. 1 Definition
The ratio of the steady-state resistance of the element in the specified concentration of interference gas and detection gas under specified working conditions. 5.5.2 Test system diagram
The test system diagram is shown in Figure 1.
5.5.3 Test steps
a. Measure Vial according to the provisions of Article 5.2.3 b. Measure Vgl according to the provisions of Article 5.2.3
c. Calculate R, and Rdg according to formula (2) in Article 5.2.4. 5.5.4 Let the resolution be:
where: D——gas resolution, Re——stable resistance in the detection gas, kn; Rdg——stable resistance in the detection gas, kn.
5.5.5 Specified conditions
Same as the provisions in Article 5.2.5.
5.6 Characteristic concentration resistance ratio (r)
5.6.1 Definition
Under specified working conditions, the ratio of the steady-state resistance values of a pair of components under two different characteristic expansions and one detection gas. 5.6.2 Test system diagram
The test system diagram is shown in Figure 1.
5.6.3 Test steps
a. Measure Va(C,) when the concentration is C, and Vg(Cz) when the concentration is Cz according to the provisions of Article 5.2.3, b. Calculate Rag(C) and R(2) according to Formula (2) in Article 5.2.4. 5.6.4 Calculation
Characteristic concentration resistance ratio is:
Where: r——characteristic concentration resistance ratio,
Ra（C,）—steady-state resistance under concentration C, koRC.）—steady-state resistance under concentration C, kn. c>
Ra(C,)
（4）
5.6.5 Specified conditions
Same as the provisions of Article 5.2.5.
5.7 Response time ()
5. 7. 1 Definition
GB/T15653—1995
Under specified working conditions, the time required for the resistance of the element to drop (or rise) to 70% of the difference between the steady-state resistance value in clean air and the steady-state resistance value in the test gas after the element contacts the specified concentration of the test gas. 5.7.2 Test system diagram
The test system diagram is shown in Figure 1.
5.7.3 Test steps
a. Measure the steady-state resistance value R of the element in clean air according to the provisions of Article 5.1, b. Measure the steady-state resistance value Ra of the element in the test gas according to the provisions of Article 5.2. Calculate the output voltage Ve on the load resistor when the resistance drops (or rises) to 70% of the difference between the resistance value in clean air and the resistance value in the test gas according to formula (2) in Article 5.2.4. Remove the element from the test gas and place it in clean air. After the element recovers, place it back in the test gas; d. Use a stopwatch or automatic timing device to time, and use a mathematical voltmeter to monitor the output voltage on the load resistor; e. When the output voltage on the load resistor also rises (or drops) to V, the time recorded by the stopwatch or automatic timing device is the response time.
5.7.4 Specified conditions
Same as the provisions of Article 5.2.5. bzxZ.net
5.8 Recovery time (ree)
5.8. 1 Definition
The time required for the resistance of the component to rise (or fall) to 70% of the difference between the steady-state resistance value in clean air and the steady-state resistance value in the test gas after the component is separated from the test gas under specified working conditions. 5.8.2 Test system diagram
The test system diagram is shown in Figure 1.
5.8.3 Test steps
a. Measure the steady-state resistance value R of the component in clean air according to the provisions of Article 5.1: b. Measure the steady-state resistance value Raec of the element in the test gas according to the provisions of Article 5.2. Calculate the output voltage Vrd on the load resistor when the resistance rises (or falls) to 70% of the difference between the resistance value in clean air and the resistance value in the test gas according to formula (2) in Article 5.2.4. Remove the element from the test gas and place it in the clean air; continue to monitor the output voltage on the load resistor with a digital voltmeter and use a stopwatch or automatic timing device to time at the same time. When the output voltage on the load resistor drops (rises) to V, the time recorded by the stopwatch or automatic timing device is the recovery time.
5.8.4 Specified conditions
Same as the provisions of Article 5.2.5.
5.9 Temperature coefficient (9r)
5. 9.1 Definition
The average value of the logarithm of the ratio of the steady-state resistance of the element in the test gas of specified concentration, the relative humidity of the environment is 50% and the ambient temperature is in the range of T1~T1, and the temperature changes by 1℃. 5.9.2 Test system diagram
The test system diagram is shown in Figure 1.
5.9.3 Test steps
GB/T 15653—1995
a. According to the provisions of Article 5.2.3, measure T, temperature and voltage Va respectively.Separate the element from the test gas and place it in the clear air; continue to monitor the output voltage on the load resistor with a digital voltmeter and use a stopwatch or automatic timing device to time at the same time. When the output voltage on the load resistor drops (rises) to V, the time recorded by the stopwatch or automatic timing device is the recovery time.
5.8.4 Specified conditions
Same as the provisions of Article 5.2.5.
5.9 Temperature coefficient (9r)
5. 9.1 Definition
The average value of the logarithm of the ratio of the steady-state resistance of the element in the test gas of specified concentration, the relative humidity of the environment is 50% and the ambient temperature is in the range of T, ~T, for every 1℃ change in temperature. 5.9.2 Test system diagram
The test system diagram is shown in Figure 1.
5.9.3 Test steps
GB/T 15653—1995
a. According to the provisions of 5.2.3, measure T, temperature and voltage Va respectively.Separate the element from the test gas and place it in the clear air; continue to monitor the output voltage on the load resistor with a digital voltmeter and use a stopwatch or automatic timing device to time at the same time. When the output voltage on the load resistor drops (rises) to V, the time recorded by the stopwatch or automatic timing device is the recovery time.
5.8.4 Specified conditions
Same as the provisions of Article 5.2.5.
5.9 Temperature coefficient (9r)
5. 9.1 Definition
The average value of the logarithm of the ratio of the steady-state resistance of the element in the test gas of specified concentration, the relative humidity of the environment is 50% and the ambient temperature is in the range of T, ~T, for every 1℃ change in temperature. 5.9.2 Test system diagram
The test system diagram is shown in Figure 1.
5.9.3 Test steps
GB/T 15653—1995
a. According to the provisions of 5.2.3, measure T, temperature and voltage Va respectively.
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