This standard applies to electron tubes with anode dissipation power not exceeding 25W. It also specifies the method of filament intermittent test and the requirements for test equipment. GB/T 3307-1982 Method of intermittent test of filaments of low-power electron tubes GB/T3307-1982 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Method of heater intermittent test ofFow-power electronic tubesUDC 621.385.1
:621. 317.08
GB3307-82
This standard is applicable to electronic tubes with anode dissipation power less than 25W. It also specifies the method of filament intermittent test and the requirements for test equipment.
1 Test conditions
1.1 The filament intermittent test should be carried out under the test conditions specified in the product standard. 1.2 During the filament intermittent test, the filament voltage of the tube under test should be connected or disconnected at the same time according to the specified intermittent cycle. If the product standard does not specify, the intermittent cycle is specified as follows: a. The indirect heating type tube is connected for 2±0.5 minutes and disconnected for 2±0.5 minutes. b. The direct heating type tube is connected for 5±1 seconds and disconnected for 20±2 seconds. 1.3 During the filament intermittent test, the filament power supply can be either DC or AC. 1.4 The filament voltage applied during the filament intermittent test should generally be higher than 10% of the rated value (i.e. equal to the maximum value of the filament voltage use limit in the product standard)
1.5 The voltage between the filament and the cathode and its polarity applied during the filament intermittent test should comply with the provisions of the survival test conditions in the product standard. 1.6 During the filament intermittent test, the voltage between the filament and the cathode should not be disconnected. 1.7 During the filament intermittent test, no voltage is applied to the other electrodes. 1.8 During the filament intermittent test, the stability of the electrode voltage should meet the following requirements: a. The change in the filament voltage is not greater than ±.2%. b. The change in the voltage between the filament and the cathode is not greater than ±5%. 1.9 The filament intermittent test shall be carried out under normal atmospheric conditions specified in GB2421-81 "General Rules for Basic Environmental Test Procedures for Electrical and Electronic Products" (ambient temperature of 15~35℃, relative humidity of 45%~75% and air pressure of 86~106 dry Pa). 2 Test method
2.1 The sample extraction method and quantity of the filament intermittent test and the test status shall comply with the corresponding general technical conditions, product standards and the provisions of this standard.
2.2 Before the filament intermittent test and after the test reaches the specified number of cycles, the test tube shall be checked for the following standard parameters. a. Short circuit and open circuit:
b. Leakage current between filament and cathode: bzxZ.net
core, filament current.
Note: The inspection standard parameters of special electron tubes are specified in the product standards. 2.3. The failure criteria for judging the filament intermittent test of the test tube are: 9. Short circuit and open circuit,
b. The leakage current between the filament and the cathode exceeds the value specified in the product standard, c. Other mechanical damage that causes the electron tube to fail to operate normally. Society: The failure standard of special electron tubes is specified in the product standard. 2.4 The number of cycles of the filament intermittent test is as follows: National Bureau of Standards 1982-12-15
1983-10-01
"M" grade electron tube is 1000 times.
GE 3807—82
b. 2000 times for “T and Q” grade electron tubes. The qualified rate of “T and Q” grade electron tubes in the first 500 intermittent cycles shall be 100%. Note: The number of cycles for special electron tubes is specified in the product standard. 2.5 During the filament intermittent test, any tube under test is considered to have failed as long as its electrical parameters exceed the failure standard or there is damage in terms of mechanical strength.
2. The number of cycles of a failed single tube under test is the number of times the test has been carried out when the tube is found to have failed. .7 The qualification assessment of the filament intermittent test of each batch of electron tubes shall be carried out in accordance with the provisions of the corresponding general technical conditions. 2.8 The measurement of the failure standard parameters of the tube under test shall be carried out in accordance with the test methods specified in the corresponding national standards. . 2.9 During the filament intermittent test, the test status of the test tube and the working condition of the test equipment should be checked regularly, and records should be made of abnormal conditions.
2.10 The filament intermittent test report for each batch of tubes should include the report number, test tube model, quantity, manufacturing time, test basis, test time, test records and test conclusions. 3 Requirements for test equipment
3.1 The various special equipment used for the filament intermittent test should comply with the provisions of GB3306:1-82 "Test methods, test equipment and general electrical tests for small power electron tubes" and this standard. 3.2 Unless otherwise specified in the product standard, the filament circuits of the test tubes should be connected in parallel. 3.3 When the filament power supply is connected to the tube socket of the test tube, Ensure that when the equipment is fully loaded, the difference between the filament voltage on any test tube socket and the indicated value of the filament voltmeter should not exceed 2.5%. 3.4 When the equipment is fully loaded, the internal resistance of the filament power supply should meet the following requirements: a. For indirectly heated electron tubes, it should be ensured that when the test state is the instant of connection, the change in its filament voltage is no more than 10% of the steady state (specified value).
b. For directly heated electron tubes and electron tubes with a rated voltage less than 1.5V, it should be ensured that it is no more than 20% of the total filament resistance at the rated filament voltage.
3.5 The voltage between the filament and the cathode can be supplied by one or more power supplies, and it is also allowed to be supplied by a voltage divider. And add between the cathode of the electron tube and the midpoint of the secondary winding of the filament transformer, or between the electron Add between the tube cathode and the midpoint of the voltage divider connected in parallel with the secondary winding of the filament transformer. If the voltage between the filament and the cathode is more than 10 times higher than the filament voltage, the voltage is allowed to be added between the cathode of the electron tube and any end of the secondary winding of the filament transformer. 3.6: The internal resistance of the power supply between the filament and the cathode should ensure that the power supply voltage does not change by more than 5% when the equipment is fully loaded and the maximum allowable leakage current between the filament and the cathode.
3.7 The ripple factor of the DC power supply voltage used in the filament intermittent test should not exceed 5%, and the waveform distortion factor of the AC power supply voltage used should not exceed 5%.
3.8 The filament voltage interrupter should ensure the on-off cycle of the filament voltage. The filament voltage interrupter is allowed to be connected to the secondary circuit of the filament transformer.
3.9 The filament intermittent test equipment should be equipped with a counter to record the number of cycles. 3.10 The filament intermittent test equipment should be equipped with an indicator to monitor whether there is a short circuit between the filament and the cathode. The resistance of the indicating device should be such that when the maximum allowable leakage current flows between the filament and the cathode, the voltage drop generated on it should not exceed 5% of the voltage between the filament and the cathode specified in the product standard. 3.11 The instruments used on the filament intermittent test equipment should meet the following requirements: a. The accuracy of the AC or DC instrument for determining the filament voltage should not be lower than Class 1.5. b. The accuracy of the DC instrument for determining the voltage between the filament and the cathode should not be lower than Class 1.5, and the accuracy of the AC instrument should not be lower than Class 2.5. 3.12 Electrical schematic diagram of filament intermittent test (taking the indirectly heated electron tube as an example) Additional notes:
This standard was proposed by the Ministry of Electronics Industry.
GB 33 07 --82
This standard was drafted by Shuguang Electron Tube Factory and other units.
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