This standard specifies the test method for the transconductance and amplification factor of the transmitting tube. This standard is applicable to the test of the transconductance and amplification factor of the space charge controlled oscillation, modulation, adjustment and power amplifier tube with anode dissipation power above 25W. GB/T 3789.6-1991 Transmitter tube electrical performance test method Transconductance, amplification factor test method GB/T3789.6-1991 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods for electrical properties of transmitting tubes
Test methods for transconductance and amplification factor
Measuremnents of the electrical properties of transmitting tubesMcesuring methods of trantsconductazce nd arnplification factor1 Subject content and scope of application
This standard specifies the test methods for transconductance and amplification factor of transmitting tubes. GB/T 3789.6-91
Replaces GB 3789.6—83
This standard applies to the test of transconductance and amplification factor of space charge controlled oscillation, modulation, adjustment and power amplifier tubes with anode power consumption of more than 25W.
2 Reference standards
GB/T3789.1 General principles for testing the electrical properties of transmitting tubes 3 Terms
3.1 Transconductance
Transconductance refers to the ratio of the increment of the anode current to the corresponding increment of the first grid voltage when the anode voltage and other voltages remain constant under the specified working conditions.
3.2 Amplification factor Amplification factor refers to the ratio of the increment of the anode voltage to the corresponding increment of the first grid voltage when the anode current and other voltages remain constant under the specified working conditions.
3.3 Internal amplification factor amplification factor of grid N2 to grid N1 The internal amplification factor refers to the ratio of the increment of the second grid voltage to the corresponding increment of the first grid voltage when the anode current and other voltages remain constant under the specified working conditions. 4 Schematic diagram bzxZ.net
Figure 1 Schematic diagram of DC test circuit
Approved by the State Administration of Technical Supervision on August 15, 1991 and implemented on April 1, 1992
In Figure 2:
· Pulse signal generator:
GB/T 3789. 6-91
Figure 2 Schematic diagram of pulse test circuit
Non-inductive resistor. Its error is not more than 1%, and the resistance value should meet the following requirements: R0. 03 Rmln
Where: Ridn-
The minimum internal resistance of the electron tube when it is turned on;
When the R resistance value is small, the influence of the wire and contact resistance should be considered. Due to the influence of heat dissipation, the change in resistance value should not exceed ±0.5% of the normal value.
-Capacitor. The capacity should meet the following requirements:
Ra, Re2
-Resistors. The resistance value should meet the following requirements:
Where: T--pulse width,
T--pulse period;
P--pulse drop coefficient
R2n--equivalent minimum resistance between the second gate and cathode when the electron tube is turned on. Z,1--resistor (B,) or inductor (I). The DC voltage drop on it should not exceed 0.5% of the DC voltage of the first grid; C,1--capacitor. Its selection condition: when the grid pulse current flows through, the voltage drop on the capacitor should not exceed 1% of the pulse amplitude: Pi, P--pulse voltmeter (or oscilloscope). 5 Test equipment and test rules
Test equipment and test rules should meet the requirements of GB/T3789.1. 6 Test methods
6.1 Transconductance test
6.1.1 Test method of Figure 1
6.1.1.1 Add the filament voltage and other pole voltages according to the specifications. 6.1.1.2 Under the condition of keeping the anode voltage and other grid voltages and filament voltages at constant values, adjust the first grid voltage so that the anode current reaches the corresponding specified values ​​I\ and I\. And record the corresponding first grid voltage values ​​U and U\ respectively. Or adjust the first grid voltage to the smaller specified value U, and record the anode current value I. Then adjust the first grid voltage to the larger specified value U,\, and record the anode current value I,\. 6.1-1.3 The transconductance is calculated according to formula (1):
U\ -H!
6.1.2 Test method of Figure 2
6.1.2.1 Add the filament voltage and the DC voltage of each pole according to the specification. (1)
6.1.2.2 While keeping the anode voltage, other grid voltages and filament voltage at constant values, adjust the first grid pulse voltage so that the anode pulse current reaches the corresponding specified values ​​Iap and I\, and record the corresponding first grid pulse voltage values ​​UIu and Uis\ respectively. Or adjust the first grid pulse voltage to a smaller specified value and record the anode pulse current value 1. Then adjust the first grid pulse voltage to a larger specified value Ui\ and record the anode pulse current value I\. 6.1.2.3 The transconductance is calculated according to formula (2):
6. 2 Test of amplification factor
6.2.1 Test method of Figure 1
Tap\ I'
Uein\ _ U,t'
6.2.1.1 Add the filament voltage and other pole voltages according to the specification, +(2)
6.2.1.2 Under the condition that the voltages of other poles are kept constant, the anode voltage is the specified larger value 1. > Adjust the first grid voltage so that the anode current reaches the specified value, and record the corresponding first grid voltage value. 6.2.1.3 Keep the voltages of other poles constant, reduce the anode voltage to the specified value 0.\ according to the specification, adjust the first grid voltage so that the anode current remains unchanged, and record the first grid voltage value U,\ at this time. 6.2.1.4 The amplification factor is calculated according to formula (3): U —U\
U, -U,\
6.2.1.5 The internal amplification factor is tested by changing the second grid voltage and the first grid voltage under the condition of keeping the anode current and other pole voltages at constant values. The test method is the same as above. The internal amplification factor is calculated according to formula (4):
Ue—ts\
6. 2. 2 Test method of Figure 2
6.2.2.1 Add the filament voltage and the DC voltage of each pole according to the specification. (4)
6.2.2.2 Under the condition of keeping the voltages of other poles at constant values ​​(the anode voltage is the specified larger value U!), add a specified positive pulse voltage to the first grid, adjust the negative voltage of the first grid, so that the anode current reaches the specified value, and record the negative voltage value of the first grid at this time U,. 6.2.2.3 Keep the voltages of other electrodes at constant values, reduce the anode voltage to the specified value U.\ according to the specification, adjust the negative voltage of the first grid, keep the anode current unchanged, and record the negative voltage value of the first grid at this time U.1\. 6.2.2.4 The amplification factor is calculated according to formula (5), UU.n
6.2.2.5 The internal amplification factor is tested by adjusting the second grid voltage and the first grid negative voltage under the condition of keeping the anode current and anode voltage and other electrode voltages at constant values. The test method is the same as above. The internal amplification factor is calculated according to formula (6):
GB/T 3789. 691
Ua' -Ua\
Note: The test accuracy of Figure 1 is higher, and it is recommended to be used first in product inspection, but it should be noted that the dissipated power of each electrode should not exceed the limit value. Additional remarks:
This standard is proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. This standard is drafted by the Electronic Standardization Institute of the Ministry of Machinery and Electronics Industry and Factory 779. (6)
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