This standard specifies the test method for the electrical properties of low-power electron tubes and the requirements for test conditions. This standard applies to electron tubes with anode dissipation power not exceeding 25W. GB/T 3306-2001 Test method for the electrical properties of low-power electron tubes GB/T3306-2001 Standard download decompression password: www.bzxz.net

GB/T3306—2001
This standard includes 23 test methods for the electrical properties of low-power electron tubes. This standard is based on GB/T1.1-1993 "Guidelines for Standardization Work Unit 1: Drafting and Expression Rules of Standards Part 1: Basic Regulations for Standard Writing" and GB/T2987-1996 "Electronic Tube Parameter Symbols", GB/T4597-1996 "Electronic Tube Vocabulary", GB3100~3102-1993 "Quantities and Units", GB/T5094-1985 "Project Codes in Electrical Technology" and GB/T4728.5-2000 "Graphical Symbols for Electrical Diagrams Semiconductor Tubes and Electron Tubes", and also refers to the International Electrotechnical Commission IEC100:1969 GB/T3306.1～3306.24-1982 "Test Method for Electrical Performance of Low-Power Electron Tubes" was revised by "Test Method for Electrode Capacitance of Electron Tubes", IEC151-1:1963 "Test Electrode Current for Test of Electrical Performance of Electron Tubes", IEC151-5:1964 "Test Sound and Hum for Test of Electrical Performance of Electron Tubes", EC151-7,1964 "Test Equivalent Noise Resistance for Test of Electrical Performance of Electron Tubes", and EC151-12:1966 "Test Method for Electrode Resistance, Transconductance, Amplification Factor, Audio Resistance and Frequency Conversion Transconductance for Test of Electrical Performance of Electron Tubes". In this revision process, the standard format of GB/T3306.1～3306.24-1982 was greatly changed. GB/T3306.1～3306.24-1982 was written in the form of 24 sub-standards. This standard is written in a standard format with the test equipment and electrical test general principles and 23 test methods in GB/T3306.1~3306.24-1982, and the errors in GB/T3306.1~3306.24-1982 are corrected. The parameter symbols are modified, and the quantities and units in the standard are standardized. All test circuit diagrams and structural schematic diagrams in this standard are added with figure titles, the electrical project codes in the test circuit diagrams and the graphic symbols used for electrical schematics are revised, and unnecessary comments in GB/T3306.1~3306.24-1982 are deleted. Through the revision of this standard, the test sequence is clearer and more rigorous. Appendix A, Appendix B, Appendix C, Appendix D, and Appendix E of this standard are the appendices of the standard. Appendix F of this standard is a prompt appendix.
This standard is proposed by the Ministry of Information Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Vacuum Devices. The drafting unit of this standard: Shuguang Electronics Group Co., Ltd. The main drafters of this standard are Long Jixue and Zhou Weiqiu. This standard was first issued in December 1982. I
1 Scope
National Standard of the People's Republic of China
Measurements of the electrical properties of low-power electron tubes
GB/T3306—2001
Replaces GB/T3306.1~3306.24—1982 This standard specifies the test methods and test conditions for the electrical properties of low-power electron tubes (hereinafter referred to as electron tubes). This standard is applicable to electron tubes with anode dissipation power not exceeding 25W. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2421—1999 Environmental testing for electric and electronic products Part 1: General (idtEC60068.1—1988) Dimensions of electron tubes
GB/T3188-—1982
GB/T4597—1996
Vocabulary of electron tubes
3 Definitions
Unless otherwise specified, the definitions used in this standard shall comply with the provisions of GB/T4597. 4 General requirements
The test equipment used for testing and the general requirements for testing shall meet the provisions of 4.1 to 4.4. Unless otherwise specified, the test shall be carried out under the following conditions. 4.1 Test equipment
4.1.1 The test equipment shall be calibrated regularly by the metrology department and used within the validity period. 4.1.2 Each test equipment shall be accompanied by:
a) the instruction manual of the equipment;
b) the circuit diagram of the equipment;
c) the inspection certificate of the electrical test instrument.
4.1.3 The insulation resistance between the electrode circuits of the unconnected electron tubes under test on the test equipment shall not be less than 200MQ. When testing the insulation resistance, the power supply, test instrument and circuit conductive elements shall be disconnected from the jacks and switching points. If the current of the electron tube test is less than 100uA, the leakage current caused by poor insulation shall be less than 5% of the current value under test. When the tested current is less than 5μA, the test error caused by poor insulation shall be less than 20%. If the above requirements cannot be met, compensation and other methods are allowed.
When testing the insulation resistance or leakage current, the maximum adjustable DC voltage of the electrode shall be added to the conductive pin of the tube socket under test. 4.1.4 During the test, if the cathode specification is determined by the specified value of the hot wire (filament) voltage, this voltage shall be measured by a voltmeter. The voltage drop on the lead wire between the voltmeter and the tube socket shall not exceed 0.2% of the rated voltage of the hot wire (filament), and the current passing through the voltmeter shall not exceed 0.5% of the hot wire (filament) current; if the cathode specification is determined by the specified value of the hot wire (filament) current, this current shall be measured by an ammeter. When the ammeter is connected, it shall be ensured that the current of the circuit elements (voltmeter and voltage divider in the hot wire (filament) circuit) that are shunted from the hot wire (filament) does not flow through the ammeter, and the voltage drop on the ammeter shall ensure that the voltage drop on the lead wire between the voltmeter and the tube socket does not exceed 1% of the rated voltage of the hot wire (filament).
4.1.5 When determining the DC voltage value and polarity of each electrode of the electron tube, if there is no provision in the test method standard or the detailed specification of the electron tube, it refers to the common point of the circuit. 4.1.6 When testing directly heated electron tubes, the common point of the circuit should be: a) When the filament is powered by DC, the common point of the circuit is the negative end of the filament. The positive and negative ends of the filament lead wires should be specified in the detailed specification of the electron tube.
b) When the filament is powered by AC, the common point of the circuit is the center point of the secondary coil of the transformer supplying the filament power or the center point of the filament power divider.
The resistance of the divider should be such that the current value passing through it is not less than 20 times the cathode current value of the tube being tested. 4.1.7 When testing indirectly heated electron tubes, the common point of the circuit should be the lead-out terminal of the cathode of the tube being tested. If the test is carried out under the condition that a self-supplied bias resistor is connected in the cathode circuit, the common point of the circuit should be specified in the detailed specification of the electron tube. When it is not specified, the circuit common point shall be the end of the resistor not connected to the cathode.
4.1.8 When testing electron tubes with metal casings and internal shields (the internal shield is not connected to the cathode inside the tube), these leads should be connected to the circuit common point.
When the suppression grid is not connected to the cathode inside the tube, and when it is not specified in the detailed specifications of the electron tube, it should be connected to the cathode. 4.1.9 When testing electron tubes with self-supplied bias, the cathode circuit components shall meet the following requirements: a) The difference between the cathode circuit resistance value and the specified value does not exceed ±1% b) When the cathode current has an AC component, the cathode circuit resistance should be bypassed by a capacitor. Its capacitive reactance should be less than 0.3% of the resistance value of the resistor.
The test equipment and preheating equipment should avoid parasitic oscillations in the tube under test and the preheating tube. For this purpose, some auxiliary components should be used. For example: a) directly connect decoupling resistors and chokes in series in the electrode circuit of the tube socket under test; b) connect bypass capacitors between any electrode and cathode and between other electrodes; c) put iron-coated oxygen magnetic rings on the conductor;
d) add decoupling filters to the power supply, etc.
When using the above-mentioned components and circuits to prevent parasitic oscillations, the test conditions should not change significantly, and the test accuracy should not be reduced.
4.1.11 If there are test instruments, components of protection devices and components to prevent parasitic oscillations in the electrode circuit with a positive potential to the cathode, when the rated current of the electrode flows through it, the DC voltage drop generated on it should not exceed 0.5% of the rated voltage of the electrode.
For the anode circuit of tetrodes and pentodes, the voltage drop should not exceed 1.5% of the anode voltage. 4.1.12 The preheating position of the preheating equipment and the test equipment shall meet the following requirements: a) The electronic tube shall be guaranteed to maintain the specified preheating time in the preheating state, but the efficiency of the test equipment shall not be reduced; b) In the preheating state, the resistance value of the resistor connected to the cathode and control grid circuit shall be specified in the detailed specifications of the electronic tube. The error of the cathode circuit resistance shall not exceed ±5% of the specified value; the control grid circuit resistance shall not exceed ±10% c) A buffer indicator bulb and an overload protection device shall be connected in series in the anode and screen grid circuits of a group of electronic tubes (single or multiple electronic tubes) and the circuit between the hot wire and the cathode. However, its influence on the electrode voltage shall not exceed 5% of the rated voltage. If it exceeds this regulation, it shall be corrected.
4.1.13 When testing electronic tubes, if the electric field, magnetic field and other factors have a considerable influence on the test results, effective measures shall be taken to eliminate their influence on the test.
4.2 Requirements for electrical test instruments
GB/T3306—2001
4.2.1 Electrical test instruments shall meet the following accuracy levelsa) The accuracy of DC instruments for testing 50Hz electron tube parameters shall not be lower than Class 1. When measuring DC voltages above 3kV, instruments with an accuracy of not less than Class 1.5 are permitted. The accuracy of electronic microammeters for testing the control grid and suppression grid currents of electron tubes, the anode current at the beginning of the anode-grid characteristic curve, and the insulation resistance between the hot wire and the cathode, etc., shall not be lower than Class 4. The accuracy of DC or AC instruments for determining the preheating specifications of electron tubes shall not be lower than Class 2.5. b) The accuracy of AC instruments for testing 50Hz electron tube parameters shall not be lower than Class 1.5. When testing AC voltages with an effective value less than 5V and a frequency greater than 50Hz, and when the instrument needs to have a high input impedance according to the test specifications, electronic voltmeters or other instruments with an accuracy of not less than Class 2.5 (the scale is the effective value) are permitted. c) The accuracy of the instrument used to test the short circuit and open circuit of the electron tube, the cathode heating time, the insulation resistance between the lead wires and the hum shall not be lower than Class 2.5.
The error of the electronic pulse instrument for testing the current and voltage pulse value shall not exceed ±6% of the upper limit of the working scale. 4.2.2 When calibrating the electrical test instrument on the test equipment, in principle, the instrument should not be removed from the working position of the test equipment. At the same time, the calibration should be carried out at the specified working temperature of the equipment. 4.2.3 When testing the electron tube, it is allowed to use other electrical test instruments (such as automatic indicating devices or digital instruments, etc.) to replace the electrical test instrument, but its error should not exceed the error of the electrical test instrument. 4.2.4 Selection of the range of the electrical test instrument: During the test, the reading of the standard value added to each electrode of the electron tube and the measured parameters should be guaranteed to be within a range greater than 1/3 of the instrument scale as much as possible.
Note: Electronic instruments are allowed to read within the full range scale. 4.2.5 In order to protect the instrument from sudden overload, various protection devices are allowed to be used on the test equipment. For example: electromagnetic relays, electronic relays and switching tubes.
When a protective device is connected to a circuit with an AC component, the test conditions should not be affected and the test accuracy should not be reduced. 4.3 Power supply requirements
4.3.1 The DC power supply used by the test equipment should use an electronic voltage stabilizer or other voltage stabilizer to stabilize the voltage. If the voltage stabilization requirements can be met, other forms of DC power supplies are also allowed. For example: batteries and dry batteries, etc. 4.3.2 When testing directly heated electron tubes, the filament circuit of the tube under test must be powered by DC. The filament circuit is allowed to be powered by AC only when testing rectifier diodes and when there are clear provisions in the detailed specifications of the electron tube. When testing indirectly heated electron tubes, the hot filament circuit of the tube under test can be powered by DC or AC.
4.3.3 When the load is the maximum allowable value, the power supply ripple factor measured on the tube socket of the tube under test should not exceed the following provisions: a) Hot wire (filament) power supply - 1.5% for direct-heated electron tubes; 5% for indirectly-heated electron tubes; b) Control grid power supply 0.1%;
c) Anode and other grid power supplies 0.2%
d) Other power supplies and power supplies above 1kV 5%. Note: When testing a single parameter, when the ripple factor of the power supply makes the error of its test value exceed the specified measurement error, the ripple factor of the above-mentioned power supply should be reduced accordingly.
4.3.4 The internal resistance of the DC power supply used to supply the anode and the grid circuit with positive potential to the cathode should ensure that the power supply voltage does not change by more than 1% when the load changes from zero to maximum. 4.3.5 The internal resistance of the DC power supply used to supply the hot wire (filament) should ensure that the power supply voltage does not change by more than 2% when the load changes from zero to maximum.
4.3.6 In the test method, the form of the AC power supply (including pulse power supply) and the basic requirements for the power supply should be specified. When testing under the rectified state, it is allowed to use an AC power supply transformer with a frequency of 50Hz as the AC power supply added to the electrode, and its waveform distortion coefficient should not exceed 5%. And when the power supply voltage changes from -15% to +5%, the stability should not be less than 1.5%. 4.3.7 The minimum voltage change value of the electrode voltage adjustment device should not exceed 0.5% of the corresponding electrical test instrument range. It is allowed to use coarse adjustment and fine adjustment methods for adjustment.
4.3.8 When using a common instrument, the conversion of the test instrument should ensure that the change of the electrode voltage of the measured tube does not affect the accuracy of the parameter test before and after the conversion. To eliminate its influence, it is recommended to adopt the following measures: a) Use a low internal resistance power supply and a high internal resistance voltmeter; b) When the instrument is disconnected, a resistor with the same internal resistance as the instrument should be connected to the circuit. 4.3.9 The DC power supply connected to the circuit with AC component shall have the minimum internal resistance for the specified AC component. For this purpose, it is allowed to bypass the DC power supply with a capacitor.
4.3.10 The electrode power supply at the preheating position of the preheating device or test equipment shall meet the following requirements: a) The transformer power of the hot wire (filament) circuit shall ensure that when the number of preheated electron tubes changes by 20%, the change of the hot wire (filament) voltage shall not exceed 10%;
b) The internal resistance of the DC power supply shall ensure that when the number of preheated electron tubes changes by 20%, the change of the electrode voltage shall not exceed 10%; c) The power supply ripple factor shall not exceed the following values: 1) Anode voltage is 5%;
2) Control grid voltage is 1%;
3) Other grid voltages are 2%.
4.3.11 The pulse width and repetition frequency of the pulse power supply voltage shall comply with the provisions in the detailed specifications of the electron tube. The pulse waveform and its parameters shall comply with the provisions of Figure 1:
Figure 1. Pulse waveform and its parameters diagram
In Figure 1:
- Pulse width. Refers to the time occupied by the pulse waveform width at the level of 70% of the pulse amplitude. - Pulse rise time. Refers to the time required for the pulse amplitude to rise from 10% to 90%. Pulse fall time. Refers to the time required for the pulse amplitude to fall from 90% to 10%. Ap
- Pulse amplitude. It is determined by the height of the pulse waveform at the midpoint of the smooth line XY (excluding the wave tip) drawn by the average value of the pulse waveform top change.
Pulse top drop. It is determined by the difference between the maximum pulse amplitude and the minimum pulse amplitude where the smooth line XY (excluding the wave tip) drawn by the average value of the pulse waveform top change intersects with the pulse waveform. S--wave tip. Refers to a short-term sudden change in the pulse amplitude. Its value shall not exceed 5% of the pulse amplitude. 4
4.4 Requirements for equipment structure
GB/T3306—2001
4.4.1 The test equipment can be comprehensive (i.e. one device can test multiple tube types or several parameters) or dedicated. 4.4.2 The test equipment should have protective devices.
4.4.3 The structure of the test equipment should be easy to maintain, and its main parts and components should have markings consistent with the schematic diagram or wiring diagram. At the same time, the structure of the test equipment must meet the technical safety requirements, and the common point of its circuit should be connected to the skeleton. 4.4.4 If the test equipment is used under significant vibration and bumps, a vibration reduction device should be added. 4.4.5 The wiring and parts of the test equipment should be firmly fixed and must be guaranteed not to be damaged during transportation. 4.4.6 The pipe socket on the test equipment must ensure firm contact with the tested pipe under the condition that the tested pipe is frequently plugged in and out. 4.4.7 The preheating device can be designed as a separate device or as a component of the test equipment. It is permitted to use an automatic switching device to switch the electron tube from the preheating state to the test state. 4.4.8 The structure of the test equipment and preheating device must ensure that the ambient temperature of the electrical test instrument does not exceed its specified value during operation. 4.4.9 The layout of the control mechanism of the electrical test instrument on the test equipment and the tube socket of the tested tube must ensure easy operation. 4.4.10 The arrangement and fixed position of the electrical test instruments on the test equipment and preheating equipment must avoid the influence of external electric fields, magnetic fields and other factors.
4.4.11 The structure of the test equipment should ensure that the calibration of its instruments is convenient. 4.4.12 When a scale-free automatic indicating device is used to calibrate the preheating and test status of the electron tube, or the test parameters, the equipment should have a device for calibrating and adjusting the automatic indicating device with electrical test instruments. 4.4.13 The AC and DC power supplies for each electrode should be designed in the same device as much as possible. 4.4.14 The setting of the AC power supply in the test equipment should not affect the instrument test accuracy. 4.5 General provisions for electrical testing
4.5.1 When testing electron tubes, the preheating status, preheating time, test sequence and method should be specified in the detailed specifications of the electron tube. Note
1 The time required to move or switch the electron tube from the preheating position to the test position should not exceed 3s. 2 The test of each parameter should be carried out after the instrument indication is stable. 4.5.2 When testing Li Sheng tubes, if there is no provision in the test method standard or in the detailed specifications of the electron tube, the symmetrical electrode units should not be connected in parallel.
4.5.3 When testing a unit of a composite tube or Li Sheng tube without internal shielding, if there is no provision in the test method standard of the electron tube, the voltage of the other unit should meet the following requirements: a) It should not exceed the given test range when not sharing the cathode; b) It should be equal to the electrode voltage of the unit under the current characteristic conditions of the anode working point when sharing the cathode. It is recommended to test two units simultaneously when testing composite tubes or Li Sheng tubes.
4.5.4 It is allowed to measure n parameters simultaneously without affecting the measurement accuracy and without contradicting the test method. 4.5.5 If there are special provisions in the detailed specifications of the electron tube, it is allowed to test the gate current when the gate is applied with AC voltage. At this time, the test of the gate current can be carried out simultaneously with the test of other parameters (for example: the test of the gate current of the frequency converter tube is carried out simultaneously with the test of the frequency converter transconductance). 4.5.6 When the electron tube is preheated or tested, the voltages of each electrode should be connected at the same time, or in the following order: a) connect the hot wire (filament) voltage;
b) connect the grid voltage with a negative potential to the cathode; c) connect the anode voltage;
d) connect the voltages of the remaining electrodes.
4.5.7 When the electron tube electrode voltages are disconnected, they can be disconnected at the same time or in the opposite order of connection. 4.5.8 When testing the electron tube, it should be carried out under normal atmospheric conditions specified in GB/T2421 (ambient temperature is 15℃~35℃, relative humidity is 45%~75% and air pressure is 86kPa~106kPa). 5
GB/T3306—2001
5 Test method for anode current and grid current with positive potential to cathode 5.1 Test method for anode current
5.1.1 Test method for anode current at DC voltage 5.1.1.1 The anode current shall be tested at the operating point or under the condition of the anode-grid starting characteristics specified in the detailed specification of the electron tube. 5.1.1.2 The test circuit diagram for anode current is shown in Figure 2 (taking the circuit diagram for testing the anode current of a tetrode with a fixed bias voltage as an example).
Figure 2 Test circuit diagram for anode current
5.1.1.3 When testing the anode current of a composite tube or a Lisheng tube, if each has a separate cathode lead, a resistor shall be connected in each cathode circuit under the condition of self-bias. At this time, the difference in voltage drop on the resistor due to the difference in cathode current shall not be considered. 5.1.1.4 For composite tubes and Li Sheng tubes without internal shielding, when the anode current of one unit is tested on the anode-grid starting characteristic curve, the anode current of the other unit shall be equal to the rated anode current at the working point of the characteristic curve, and the error shall not exceed 20%. However, the anode voltage shall be equal to 40% to 60% of the anode voltage applied to the unit under test. 5.1.1.5 The test of diode anode current shall be carried out by connecting a fixed resistor (including the internal resistance of the ammeter) in series in the anode circuit of the electron tube. Its resistance value shall be specified in the detailed specification of the electron tube. 5.1.1.6 The test circuit diagram of diode anode current is shown in Figure 3. Figure 3 Test circuit diagram of diode anode current The resistance R in Figure 3 shall not differ from the specified value by more than 5%. 5.1.2 Test method of anode current when pulse voltage is applied to the control electrode 5.1.2.1 The anode current tested by this method is determined under specified conditions according to the peak value of the pulse current. 5.1.2.2 The circuit diagram for testing anode current is shown in Figure 4 (taking the circuit diagram for testing anode current of pentode as an example) 6
GB/T3306—2001
Figure 4 Circuit diagram for testing anode current
The main components in Figure 4 should meet the following requirements: R
G1-rectangular pulse voltage oscillator. Its pulse waveform is allowed to have the following errors: the pulse rise time should not be greater than 20% of the pulse width, and the pulse fall time should not be greater than 30% of the pulse width; the ratio of the difference between the maximum and minimum values ​​of the pulse voltage to the pulse amplitude should not be greater than 10%.
The pulse width of the test anode pulse current should be 1us~2ms, and the duty cycle should not be less than 1/10. Ri
-resistor. Its resistance value should be given, and the error should not exceed 1%, and it should meet the following conditions: U.
Where: U. Given anode voltage;
Iapmax
-given maximum anode pulse current. When the reactance component of resistor R1 is such that the change in its resistance is no more than 1%. When the frequency is
Pe, Pe
Ugl, U.2
-pulse voltmeter or oscilloscope.
-pulse voltmeter or oscilloscope (scaled in current units). (1)
-anode power supply voltage, the internal resistance of which should be such that the voltage drop generated when the pulse current flows through the triode does not exceed 0.5% of the anode voltage; for tetrodes and pentodes, it should not exceed 1.5%. Control grid and screen grid power supply voltage. Its internal resistance should be such that the voltage drop generated when the pulse current flows through does not exceed 0.5% of the voltage of each electrode.
5.1.3 The test of anode current should be carried out in the following order: a) Determine the given electrode voltage using instruments Pi, P2, P: and P4; b) From instrument P. The anode current value is read out in the test. Note: The value of the control grid voltage U should be selected to be sufficient to cut off the tube under test during the pulse interval. 5.2 Test method for grid current with positive potential to the cathode 5.2.1 Test method for grid current with positive potential to the cathode under DC voltage The test circuit diagram of the grid current is shown in Figure 5 (taking the circuit diagram for testing the screen grid current of a pentode with a self-biased control grid as an example).
GB/T3306—2001
Figure 5 Test circuit diagram of grid current
In this case, when individual requirements in 4.1 to 4.4 cannot be met (for example: the grid with positive potential to the cathode is a small voltage and a large current), the grid voltmeter can be directly connected to the grid. At this time, the current of the voltmeter should not exceed 0.5% of the grid current. 5.2.2 Test method for grid current with positive potential to the cathode when a pulse voltage is applied to the control grid. 5.2.2.1 The grid current tested by this method is determined under specified conditions according to the peak value of the pulse current. 5.2.2.2 The test circuit diagram of the grid current is shown in Figure 4. The resistance value of resistor R2 in the figure should be given, and its error should not exceed 1%, and should meet the following conditions: R2≤0.01
Ig2peax
Where: Us2——given screen grid voltage; Ig2pmax
——given maximum value of screen grid pulse current; when the frequency is
, the reactance component of resistor R2 should make its resistance change no more than 1%. 2T
6 Test method for grid current with negative potential to cathode 6.1 Requirements
·(2)
6.1.1 The grid current with negative potential to cathode is determined by the current value passing through the grid circuit. According to the magnitude of the negative potential of the gate, the grid current can be positive grid current or negative grid current. 6.1.2 Methods not specified in this standard but necessary for testing a certain component of the grid current of certain tube types should be specified in the detailed specifications of the electron tube.
6.2 Test method
6.2.1 Direct reading method
6.2.1.1 The test circuit diagram of the gate current is shown in Figure 6 (taking the circuit diagram for testing the gate current of the pentode as an example) d
Figure 6 Test circuit diagram of the gate current
The microammeter in the figure should be electronic, and its resistance should be selected so that the voltage drop on it is not greater than 5% of the gate voltage. It is also allowed to use a magnetoelectric microammeter. At this time, a protective resistor must be connected in series with the microammeter, and its total voltage drop should also be less than 5% of the gate voltage. The sum of the microammeter resistance value and the protective resistor value should not exceed 10% of the gate circuit resistance value specified in the detailed specifications of the electron tube. Note
1 When the test range has been determined, the voltage drop on the microammeter and the protective resistor is not included. 8
GB/T3306—2001
2 When the microammeter resistance value is greater than the gate circuit resistance value specified in the detailed specifications of the electron tube, it is recommended to use a voltage stabilizer in the gate power supply circuit. 6.2.2 Compensation method
6.2.2.1 The method for testing the gate current is to connect a known resistor in series in the gate loop and calculate the gate current based on the voltage drop across the resistor.
6.2.2.2 The test circuit diagram for the gate current is shown in Figure 7 (taking the circuit diagram for testing the gate current of a transistor as an example) Figure 7 Test circuit diagram for the gate current
Note: The insulation resistance value between the contacts of the switch S1 in the figure should not be less than 50 times that of the resistor R1. The capacitance between the contacts should not be greater than 5pF6.2.2.3 The test of the gate current should be carried out in the following ordera) Turn on the switch, add voltage to each pole according to the value specified in the detailed specification of the electron tube, and record the value of the anode current of the milliammeter. b) Turn off the switch, change the control gate voltage so that the anode current reaches the original value, and record the corresponding control gate voltage U's. 6.2.2.4 The gate current 1. (uA) should be calculated according to the following formula: U'.-Us
Where: U. The control gate voltage when the switch is disconnected, V; U. — The specified control gate voltage, V;
— A known resistance, MQ.
...*....(3)
6.2.2.5 In order to improve the test accuracy, an anode current compensation circuit can be used to accurately indicate the slight change of the anode current; two control gate bias power supplies connected in series can also be used to adjust the control gate voltage and read the slight change of the control gate voltage. 6.2.2.6 When testing a gate current less than 10-4μA, the requirements for test equipment and test are shown in Appendix A (Appendix of the Standard). 7 Cathode current test method
The cathode current test circuit diagram is shown in Figure 8 (taking the circuit diagram for testing the cathode current of a pentode as an example) Figure 8 Cathode current test circuit diagram
The internal resistance of the milliammeter in Figure 8 should ensure that when the cathode current flows through the milliammeter, the voltage drop generated on it should meet the following conditions:9
Where: U is the voltage across the milliammeter, V;——anode current rating, mA;
S is the transconductance rating, mA/V.
8 Cathode emission current test method
8.1 Requirements
GB/T3306—2001
U≤0. 05
The cathode emission current measured by the method specified in this standard is the current value emitted from the cathode of the electron tube under the conditions of a specified DC, AC or pulse electrode voltage.
When there is no provision in the detailed specification of the electron tube, the cathode emission current test shall connect all electrodes except the cathode together.
8.2 Test method for alternating electrode voltage
8.2.1 The cathode emission current tested by this method is the current formed by the electrons emitted by the cathode and flowing through other electrodes with positive potential to the cathode under the specified state.
8.2.2 The test circuit diagram of the cathode emission current is shown in Figure 9 (taking the test circuit diagram of the cathode emission current of the tetrode as an example) P
Figure 9 Test circuit diagram of cathode emission current
The main components in Figure 9 shall meet the following requirements: G1 - sinusoidal voltage oscillator. The frequency is fixed in the range of 50Hz to 1500Hz. The internal resistance shall be selected so that when the load current of the tube under test changes from zero to the maximum possible value, the output voltage changes by no more than 2%. Pi - pulse voltmeter.
P2 - pulse voltmeter. Scaled by current amplitude value. R1 - resistor. Its resistance should be given, and the error should not exceed ±1%. And the following conditions should be met: Ri≤0.01
Where: U. is a given voltage for testing cathode emission current; Iemain
is a given minimum value of cathode emission current. 8.2.3 The test of cathode emission current should be carried out in the following order (5)
Adjust the oscillator voltage so that the reading of voltmeter P, is equal to the specified value, and record the reading of voltmeter P,. This reading should be equal to or greater than the specified minimum value of cathode emission current. 8.3 Test method for electrode voltage as DC
8.3.1 The cathode emission current tested by this method is determined by the current value flowing from the cathode to the other electrodes connected together. 8.3.2 When the cathode emission current is maximum, the ripple factor of the DC power supply should not exceed 5%. When the load changes from zero to the maximum possible value, the voltage change caused by the internal resistance should not be greater than 1%. 8.3.3 The test circuit diagram of cathode emission current is shown in Figure 10 (taking the circuit diagram of testing cathode emission current of a tetrode as an example). 10
GB/T3306—2001
Figure 10 Test circuit diagram of cathode emission current The damping time of the milliammeter should not exceed the allowed test time. 8.3.4 There are two methods for the test sequence of cathode emission current. 8.3.4.1 Under the condition of the specified cathode emission voltage, the test of cathode emission current should be carried out in the following order: a) Turn on the switch and adjust the power supply voltage so that the indication of the voltmeter reaches the specified value; b) Turn on the switch and read the cathode emission current value from the milliammeter. The test time using this method should not exceed 2s. 8.3.4.2 Under the condition of the specified minimum cathode emission current, the cathode emission current test shall be carried out in the following order: a) Turn on the switch and increase the power supply voltage until the reading of the milliammeter reaches the specified minimum cathode emission current; b) Record the reading of the voltmeter, which should be equal to or less than the specified emission voltage when measuring the cathode emission current. The test time using this method should not exceed 5s. 8.3.5 In accordance with the conditions specified in 8.3.4.2 of this standard, the circuit diagram shown in Figure 11 can also be used for testing (taking the circuit diagram for testing the cathode emission current of a tetrode as an example).
Figure 11 Test circuit diagram of cathode emission current The main components in Figure 11 should meet the following requirements: R1 - resistor. Its resistance should not be less than 10 times that of resistor R. U
- power supply voltage. Its voltage value should be selected so that the current flowing through resistor R. is equal to lenm. Pi - voltmeter. Its input resistance should not be less than 100 times that of resistor R. R. - resistor. Its resistance value shall be given, and the error shall not exceed ±2%. And the following conditions shall be met: U
Where: U. A given voltage for testing cathode emission current; A given minimum value of cathode emission current; Iemin
Note: If a current stabilizer is used in Figure 11, resistor R, can be omitted. 8.3.6 The test in accordance with Figure 11 shall be carried out in the following order: (6)
a) Turn switch S, to position 2, and turn on switch Si, adjust the power supply voltage so that the current indicated by the milliammeter is equal to the specified value of Iem;
b) Disconnect switch S1 and turn switch S2 to position 1; c) Turn on switch S1 to connect the tube under test to the circuit. At this time, read the value of voltmeter P1. This reading shall be equal to or less than the specified voltage U. value.-Us
Where: U. Control grid voltage when the switch is disconnected, V; U. — Specified control grid voltage, V;
— Known resistance, MQ. wwW.bzxz.Net
...*....(3)
6.2.2.5 In order to improve the test accuracy, an anode current compensation loop can be used to accurately indicate the slight change of the anode current; two control grid bias power supplies connected in series can also be used to adjust the control grid voltage and read the slight change of the control grid voltage. 6.2.2.6 When testing a gate current less than 10-4μA, the requirements for test equipment and test are shown in Appendix A (Appendix of the Standard). 7 Cathode current test method
The cathode current test circuit diagram is shown in Figure 8 (taking the circuit diagram for testing the cathode current of a pentode as an example) Figure 8 Cathode current test circuit diagram
The internal resistance of the milliammeter in Figure 8 should ensure that when the cathode current flows through the milliammeter, the voltage drop generated on it should meet the following conditions:9
Where: U is the voltage across the milliammeter, V;——anode current rating, mA;
S is the transconductance rating, mA/V.
8 Cathode emission current test method
8.1 Requirements
GB/T3306—2001
U≤0. 05
The cathode emission current measured by the method specified in this standard is the current value emitted from the cathode of the electron tube under the conditions of a specified DC, AC or pulse electrode voltage.
When there is no provision in the detailed specification of the electron tube, the cathode emission current test shall connect all electrodes except the cathode together.
8.2 Test method for alternating electrode voltage
8.2.1 The cathode emission current tested by this method is the current formed by the electrons emitted by the cathode and flowing through other electrodes with positive potential to the cathode under the specified state.
8.2.2 The test circuit diagram of the cathode emission current is shown in Figure 9 (taking the test circuit diagram of the cathode emission current of the tetrode as an example) P
Figure 9 Test circuit diagram of cathode emission current
The main components in Figure 9 shall meet the following requirements: G1 - sinusoidal voltage oscillator. The frequency is fixed in the range of 50Hz to 1500Hz. The internal resistance shall be selected so that when the load current of the tube under test changes from zero to the maximum possible value, the output voltage changes by no more than 2%. Pi - pulse voltmeter.
P2 - pulse voltmeter. Scaled by current amplitude value. R1 - resistor. Its resistance should be given, and the error should not exceed ±1%. And the following conditions should be met: Ri≤0.01
Where: U. is a given voltage for testing cathode emission current; Iemain
is a given minimum value of cathode emission current. 8.2.3 The test of cathode emission current should be carried out in the following order (5)
Adjust the oscillator voltage so that the reading of voltmeter P, is equal to the specified value, and record the reading of voltmeter P,. This reading should be equal to or greater than the specified minimum value of cathode emission current. 8.3 Test method for electrode voltage as DC
8.3.1 The cathode emission current tested by this method is determined by the current value flowing from the cathode to the other electrodes connected together. 8.3.2 When the cathode emission current is maximum, the ripple factor of the DC power supply should not exceed 5%. When the load changes from zero to the maximum possible value, the voltage change caused by the internal resistance should not be greater than 1%. 8.3.3 The test circuit diagram of cathode emission current is shown in Figure 10 (taking the circuit diagram of testing cathode emission current of a tetrode as an example). 10
GB/T3306—2001
Figure 10 Test circuit diagram of cathode emission current The damping time of the milliammeter should not exceed the allowed test time. 8.3.4 There are two methods for the test sequence of cathode emission current. 8.3.4.1 Under the condition of the specified cathode emission voltage, the test of cathode emission current should be carried out in the following order: a) Turn on the switch and adjust the power supply voltage so that the indication of the voltmeter reaches the specified value; b) Turn on the switch and read the cathode emission current value from the milliammeter. The test time using this method should not exceed 2s. 8.3.4.2 Under the condition of the specified minimum cathode emission current, the cathode emission current test shall be carried out in the following order: a) Turn on the switch and increase the power supply voltage until the reading of the milliammeter reaches the specified minimum cathode emission current; b) Record the reading of the voltmeter, which should be equal to or less than the specified emission voltage when measuring the cathode emission current. The test time using this method should not exceed 5s. 8.3.5 In accordance with the conditions specified in 8.3.4.2 of this standard, the circuit diagram shown in Figure 11 can also be used for testing (taking the circuit diagram for testing the cathode emission current of a tetrode as an example).
Figure 11 Test circuit diagram of cathode emission current The main components in Figure 11 should meet the following requirements: R1 - resistor. Its resistance should not be less than 10 times that of resistor R. U
- power supply voltage. Its voltage value should be selected so that the current flowing through resistor R. is equal to lenm. Pi - voltmeter. Its input resistance should not be less than 100 times that of resistor R. R. - resistor. Its resistance value shall be given, and the error shall not exceed ±2%. And the following conditions shall be met: U
Where: U. A given voltage for testing cathode emission current; A given minimum value of cathode emission current; Iemin
Note: If a current stabilizer is used in Figure 11, resistor R, can be omitted. 8.3.6 The test in accordance with Figure 11 shall be carried out in the following order: (6)
a) Turn switch S, to position 2, and turn on switch Si, adjust the power supply voltage so that the current indicated by the milliammeter is equal to the specified value of Iem;
b) Disconnect switch S1 and turn switch S2 to position 1; c) Turn on switch S1 to connect the tube under test to the circuit. At this time, read the value of voltmeter P1. This reading shall be equal to or less than the specified voltage U. value.-Us
Where: U. Control grid voltage when the switch is disconnected, V; U. — Specified control grid voltage, V;
— Known resistance, MQ.
...*....(3)
6.2.2.5 In order to improve the test accuracy, an anode current compensation loop can be used to accurately indicate the slight change of the anode current; two control grid bias power supplies connected in series can also be used to adjust the control grid voltage and read the slight change of the control grid voltage. 6.2.2.6 When testing a gate current less than 10-4μA, the requirements for test equipment and test are shown in Appendix A (Appendix of the Standard). 7 Cathode current test method
The cathode current test circuit diagram is shown in Figure 8 (taking the circuit diagram for testing the cathode current of a pentode as an example) Figure 8 Cathode current test circuit diagram
The internal resistance of the milliammeter in Figure 8 should ensure that when the cathode current flows through the milliammeter, the voltage drop generated on it should meet the following conditions:9
Where: U is the voltage across the milliammeter, V;——anode current rating, mA;
S is the transconductance rating, mA/V.
8 Cathode emission current test method
8.1 Requirements
GB/T3306—2001
U≤0. 05
The cathode emission current measured by the method specified in this standard is the current value emitted from the cathode of the electron tube under the conditions of a specified DC, AC or pulse electrode voltage.
When there is no provision in the detailed specification of the electron tube, the cathode emission current test shall connect all electrodes except the cathode together.
8.2 Test method for alternating voltage of electrode
8.2.1 The cathode emission current tested by this method is the current formed by the electrons emitted by the cathode and flowing through other electrodes with positive potential to the cathode under the specified conditions.
8.2.2 The test circuit diagram of the cathode emission current is shown in Figure 9 (taking the test circuit diagram of the cathode emission current of the tetrode as an example) P
Figure 9 Test circuit diagram of cathode emission current
The main components in Figure 9 shall meet the following requirements: G1 - sinusoidal voltage oscillator. The frequency is fixed in the range of 50Hz to 1500Hz. The internal resistance shall be selected so that when the load current of the tube under test changes from zero to the maximum possible value, the output voltage changes by no more than 2%. Pi - pulse voltmeter.
P2 - pulse voltmeter. Scaled by current amplitude value. R1 - resistor. Its resistance should be given, and the error should not exceed ±1%. And the following conditions should be met: Ri≤0.01
Where: U. is a given voltage for testing cathode emission current; Iemain
is a given minimum value of cathode emission current. 8.2.3 The test of cathode emission current should be carried out in the following order (5)
Adjust the oscillator voltage so that the reading of voltmeter P, is equal to the specified value, and record the reading of voltmeter P,. This reading should be equal to or greater than the specified minimum value of cathode emission current. 8.3 Test method for electrode voltage as DC
8.3.1 The cathode emission current tested by this method is determined by the current value flowing from the cathode to the other electrodes connected together. 8.3.2 When the cathode emission current is maximum, the ripple factor of the DC power supply should not exceed 5%. When the load changes from zero to the maximum possible value, the voltage change caused by the internal resistance should not be greater than 1%. 8.3.3 The test circuit diagram of cathode emission current is shown in Figure 10 (taking the circuit diagram of testing cathode emission current of a tetrode as an example). 10
GB/T3306—2001
Figure 10 Test circuit diagram of cathode emission current The damping time of the milliammeter should not exceed the allowed test time. 8.3.4 There are two methods for the test sequence of cathode emission current. 8.3.4.1 Under the condition of the specified cathode emission voltage, the test of cathode emission current should be carried out in the following order: a) Turn on the switch and adjust the power supply voltage so that the indication of the voltmeter reaches the specified value; b) Turn on the switch and read the cathode emission current value from the milliammeter. The test time using this method should not exceed 2s. 8.3.4.2 Under the condition of the specified minimum cathode emission current, the cathode emission current test shall be carried out in the following order: a) Turn on the switch and increase the power supply voltage until the reading of the milliammeter reaches the specified minimum cathode emission current; b) Record the reading of the voltmeter, which should be equal to or less than the specified emission voltage when measuring the cathode emission current. The test time using this method should not exceed 5s. 8.3.5 In accordance with the conditions specified in 8.3.4.2 of this standard, the circuit diagram shown in Figure 11 can also be used for testing (taking the circuit diagram for testing the cathode emission current of a tetrode as an example).
Figure 11 Test circuit diagram of cathode emission current The main components in Figure 11 should meet the following requirements: R1 - resistor. Its resistance should not be less than 10 times that of resistor R. U
- power supply voltage. Its voltage value should be selected so that the current flowing through resistor R. is equal to lenm. Pi - voltmeter. Its input resistance should not be less than 100 times that of resistor R. R. - resistor. Its resistance value shall be given, and the error shall not exceed ±2%. And the following conditions shall be met: U
Where: U. A given voltage for testing cathode emission current; A given minimum value of cathode emission current; Iemin
Note: If a current stabilizer is used in Figure 11, resistor R, can be omitted. 8.3.6 The test in accordance with Figure 11 shall be carried out in the following order: (6)
a) Turn switch S, to position 2, and turn on switch Si, adjust the power supply voltage so that the current indicated by the milliammeter is equal to the specified value of Iem;
b) Disconnect switch S1 and turn switch S2 to position 1; c) Turn on switch S1 to connect the tube under test to the circuit. At this time, read the value of voltmeter P1. This reading shall be equal to or less than the specified voltage U. value.3 Test method for direct current electrode voltage
8.3.1 The cathode emission current tested by this method is determined by the current value flowing from the cathode to the other electrodes connected together. 8.3.2 When the cathode emission current is at its maximum, the ripple factor of the DC power supply should not exceed 5%. When the load changes from zero to the maximum possible value, the voltage change caused by the internal resistance should not be greater than 1%. 8.3.3 The test circuit diagram for cathode emission current is shown in Figure 10 (taking the circuit diagram for testing the cathode emission current of a tetrode as an example). 10
GB/T3306—2001
Figure 10 Test circuit diagram for cathode emission current The damping time of the milliammeter should not exceed the allowed test time. 8.3.4 There are two methods for the test sequence of cathode emission current. 8.3.4.1 Under the condition of the specified cathode emission voltage, the test of cathode emission current should be carried out in the following order: a) Turn on the switch and adjust the power supply voltage so that the indication of the voltmeter reaches the specified value; b) Turn on the switch and read the cathode emission current value from the milliammeter. The test time of this method shall not exceed 2s. 8.3.4.2 Under the condition of the specified minimum cathode emission current, the cathode emission current test shall be carried out in the following order: a) Turn on the switch and increase the power supply voltage until the reading of the milliammeter reaches the specified minimum cathode emission current; b) Record the reading of the voltmeter, which shall be equal to or less than the specified emission voltage when measuring the cathode emission current. The test time of this method shall not exceed 5s. 8.3.5 In accordance with the conditions specified in 8.3.4.2 of this standard, the circuit diagram shown in Figure 11 may also be used for testing (taking the circuit diagram for testing the cathode emission current of a tetrode as an example).
Figure 11 Test circuit diagram of cathode emission current The main components in Figure 11 shall meet the following requirements: R1 - resistor. Its resistance shall not be less than 10 times of the resistor R. U
- power supply voltage. Its voltage value shall be selected so that the current flowing through the resistor R. is equal to lenm. Pi - voltmeter. Its input resistance shall not be less than 100 times of the resistor R. R. A resistor. Its resistance value shall be given, and the error shall not exceed ±2%. And the following conditions shall be met: U
Where: U. A given voltage for testing cathode emission current; A given minimum value of cathode emission current; Iemin
Note: If a current stabilizer is used in Figure 11, resistor R, can be omitted. 8.3.6 The test in accordance with Figure 11 shall be carried out in the following order: (6)
a) Turn switch S, to position 2, and turn on switch Si, adjust the power supply voltage so that the current indicated by the milliammeter is equal to the specified value of Iem;
b) Disconnect switch S1 and turn switch S2 to position 1; c) Turn on switch S1 to connect the tube under test to the circuit. At this time, read the value of voltmeter P1. This reading shall be equal to or less than the specified voltage U. value.3 Test method for direct current electrode voltage
8.3.1 The cathode emission current tested by this method is determined by the current value flowing from the cathode to the other electrodes connected together. 8.3.2 When the cathode emission current is at its maximum, the ripple factor of the DC power supply should not exceed 5%. When the load changes from zero to the maximum possible value, the voltage change caused by the internal resistance should not be greater than 1%. 8.3.3 The test circuit diagram for cathode emission current is shown in Figure 10 (taking the circuit diagram for testing the cathode emission current of a tetrode as an example). 10
GB/T3306—2001
Figure 10 Test circuit diagram for cathode emission current The damping time of the milliammeter should not exceed the allowed test time. 8.3.4 There are two methods for the test sequence of cathode emission current. 8.3.4.1 Under the condition of the specified cathode emission voltage, the test of cathode emission current should be carried out in the following order: a) Turn on the switch and adjust the power supply voltage so that the indication of the voltmeter reaches the specified value; b) Turn on the switch and read the cathode emission current value from the milliammeter. The test time of this method shall not exceed 2s. 8.3.4.2 Under the condition of the specified minimum cathode emission current, the cathode emission current test shall be carried out in the following order: a) Turn on the switch and increase the power supply voltage until the reading of the milliammeter reaches the specified minimum cathode emission current; b) Record the reading of the voltmeter, which shall be equal to or less than the specified emission voltage when measuring the cathode emission current. The test time of this method shall not exceed 5s. 8.3.5 In accordance with the conditions specified in 8.3.4.2 of this standard, the circuit diagram shown in Figure 11 may also be used for testing (taking the circuit diagram for testing the cathode emission current of a tetrode as an example).
Figure 11 Test circuit diagram of cathode emission current The main components in Figure 11 shall meet the following requirements: R1 - resistor. Its resistance shall not be less than 10 times of the resistor R. U
- power supply voltage. Its voltage value shall be selected so that the current flowing through the resistor R. is equal to lenm. Pi - voltmeter. Its input resistance shall not be less than 100 times of the resistor R. R. A resistor. Its resistance value shall be given, and the error shall not exceed ±2%. And the following conditions shall be met: U
Where: U. A given voltage for testing cathode emission current; A given minimum value of cathode emission current; Iemin
Note: If a current stabilizer is used in Figure 11, resistor R, can be omitted. 8.3.6 The test in accordance with Figure 11 shall be carried out in the following order: (6)
a) Turn switch S, to position 2, and turn on switch Si, adjust the power supply voltage so that the current indicated by the milliammeter is equal to the specified value of Iem;
b) Disconnect switch S1 and turn switch S2 to position 1; c) Turn on switch S1 to connect the tube under test to the circuit. At this time, read the value of voltmeter P1. This reading shall be equal to or less than the specified voltage U. value.
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