This standard specifies the test method for the reverse current of the gate of the transmitting tube. This standard is applicable to the test of the reverse current of the gate of the space charge controlled oscillation, modulation, adjustment and power amplifier tube with anode dissipation power above 25W. GB/T 3789.4-1991 Test method for the electrical performance of transmitting tubes Test method for reverse current of the gate GB/T3789.4-1991 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Test methods of electrical properties of transmitting tubes
Test methods of reverse grid current
Measurements of the electrical properties of transmitting tubesMeasuring methods of reverse gridg currentSubject content and scope of application
This standard specifies the test methods of reverse grid current of transmitting tubesGB/T 3789.4-91
Replaces GE 3789.4-83
This standard is applicable to the test of reverse grid current of space charge controlled oscillation, modulation, adjustment and power amplifier tubes with anode dissipation power of more than 25W.
2 Reference standards
GB/T3789.1 Test methods of electrical properties of transmitting tubesGeneral 3 Terminology
Reverse grid currentReverse grid current refers to the current in the grid circuit with a negative potential to the cathode under the specified working state. General introductionIt is the sum of the components such as grid thermal radiation current, ion current, leakage current and cathode electron current intercepted by the grid. 4
Electrical Schematicwww.bzxz.net
Direct Reading Test Schematic
Figure 2 Compensation Test Schematic
Approved by the State Administration of Technical Supervision on 1991-08-15 and implemented on 1992-04-01
In Figure 2:
GB/13789.491
R-resistor. The resistance value is specified in the detailed specification. The instrument for measuring the reverse current of the gate must have a bidirectional scale or a polarity conversion switch. 5 Test Equipment and Test Rules
The test equipment and test rules shall comply with the provisions of GB/T3789.1. 6 Test method
6.1 Test method for reverse grid current 6.1.1 Test method of Figure 1
Close the switches "S." and "S," and add the filament voltage and the voltages of each pole according to the specification, adjust the first grid voltage so that the anode current reaches the specified value, and keep it for a certain time (the time is specified in the detailed specification), then open the switch *S1\ and read the value of the reverse grid current. 6-7.2 Test method of Figure 2
Close the switch "S," and add the filament voltage and the voltages of each pole according to the specification, adjust the first grid voltage so that the anode current reaches the specified value, and record the value of the first grid voltage U, at this time. Open the switch "S," adjust the first grid voltage so that the anode current is still equal to the original value, and then record the value of the first grid voltage at this time. The reverse current value of the first anode is calculated according to formula (1): In -Un-U
6.2 Test method for the reverse current of the third grid (Figure 1) (1)
Close switches "St\, "S\, and adjust the voltage of the first grid according to the filament voltage and the voltage of each pole in the specification so that the anode current reaches the specified value. After keeping for a certain time (the time is specified in the detailed specification), open switch "S" and read the reverse current value of the third grid. Additional remarks:
This standard is proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. This standard was drafted by the Electronic Standardization Institute of the Ministry of Machinery and Electronics Industry and the responsible person of Factory 779.
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