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Power - Triode (over 1000V 100W) ·Triode

7855K

Rugged high-mu ceramic-metal planar triode for grid-pulsed, plate-pulsed, and continuous-wave service at frequencies to approximately 3 GHz.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
-
Base pins
-
Nominal heater
6 V / 1 A

Description

Rugged high-mu ceramic/metal planar triode for grid-pulsed, plate-pulsed, and CW service to 3 GHz.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
-
Nominal heater voltage
6 V
Nominal heater current
1 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Transconductance
0.025 S
Amplification factor
80
Max plate voltage
3500 V
Max plate dissipation
100 W
Max grid dissipation
2 W
Max cathode current
4.8 A

Promoted maximum ratings/characteristics populated from published headings; service-specific values retained in parameters.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1962 Eimac

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • The EIMAC [1]

    7855

    The EIMAC 7855 and 7855K are ruggedized high-mu

  • The EIMAC [2]

    7855

    The EIMAC 7855 and 7855K are ruggedized high-mu

  • Heater: Voltage ... ..o v ittt ittt i an e canasnns [1]

    6

    Heater: Voltage ... ..o v ittt ittt i an e canasnns 6.0:03 V

  • Heater: Voltage ... ..o v ittt ittt i an e canasnns [2]

    3

    Heater: Voltage ... ..o v ittt ittt i an e canasnns 6.0:03 V

  • Current, at [1]

    6

    Current, at 6.0 voItS . . . . . . v it ittt i it e ettt e 1.00 A

  • Current, at [2]

    1

    Current, at 6.0 voItS . . . . . . v it ittt i it e ettt e 1.00 A

  • Amplification Factor (Average): .. .. ... ii ittt nnnen

    80

    Amplification Factor (Average): .. .. ... ii ittt nnnen 80

  • Published value

    2

    2. Capacitance values for a cold tube as measured in a special shielded fixture in accordance with Electronic In-

  • Published value [1]

    3

    3. Measured with one milliampere plate current and a plate voltage of 1 kVdc.

  • Published value [2]

    1

    3. Measured with one milliampere plate current and a plate voltage of 1 kVdc.

  • DC PLATE VOLTAGE (grid pulsed)

    2500 V

    DC PLATE VOLTAGE (grid pulsed). . 2500 VOLTS

  • (plate pulsed) [1]

    3500 V

    (plate pulsed) ........... 3500 VOLTS Piate Voltage ............c0.... 2000 vdc

  • (plate pulsed) [2]

    2000 V

    (plate pulsed) ........... 3500 VOLTS Piate Voltage ............c0.... 2000 vdc

  • DC GRIDVOLTAGE [1]

    -150 V

    DC GRIDVOLTAGE . .. ........ -150 VOLTS Grid Voltage . .. ............... -75 Vdc

  • DC GRIDVOLTAGE [2]

    -75 V

    DC GRIDVOLTAGE . .. ........ -150 VOLTS Grid Voltage . .. ............... -75 Vdc

  • INSTANTANEOUS PEAK GRID CATHODE VOLTAGE Heater Voltage

    5.7

    INSTANTANEOUS PEAK GRID CATHODE VOLTAGE Heater Voltage . . . ... ... ... ..... 5.7 V

  • Grid negative to cathode [1]

    -700 V

    Grid negative to cathode . ... .. -700 VOLTS Peak Video Plate Current . . ........ 1.3 a

  • Grid negative to cathode [2]

    1.3 V

    Grid negative to cathode . ... .. -700 VOLTS Peak Video Plate Current . . ........ 1.3 a

  • PULSE PLATE CURRENT [1]

    3 A

    PULSE PLATE CURRENT . ....... 3.0 AMPERES Peak Video Grid Current. . . ... ... .. 0.8 a

  • PULSE PLATE CURRENT [2]

    800 mA

    PULSE PLATE CURRENT . ....... 3.0 AMPERES Peak Video Grid Current. . . ... ... .. 0.8 a

  • PULSE GRID CURRENT

    1.8 A

    PULSE GRID CURRENT . ... ..... 1.8 AMPERES Useful Power Output (approx.) .. ..

  • PLATE DISSIPATION{ [1]

    7855 W

    PLATE DISSIPATION{7855) . ... .. 100 WATTS Frequency ................... 1.090 GHz

  • PLATE DISSIPATION{ [2]

    100 W

    PLATE DISSIPATION{7855) . ... .. 100 WATTS Frequency ................... 1.090 GHz

  • PLATE DISSIPATION{ [3]

    1.09 W

    PLATE DISSIPATION{7855) . ... .. 100 WATTS Frequency ................... 1.090 GHz

  • ( [1]

    7856 W

    (7856K). . .. .. 10 WATTS Pulse Duration . .. ... v v v e v, 0.5 us

  • ( [2]

    10 W

    (7856K). . .. .. 10 WATTS Pulse Duration . .. ... v v v e v, 0.5 us

  • ( [3]

    0.5 W

    (7856K). . .. .. 10 WATTS Pulse Duration . .. ... v v v e v, 0.5 us

  • GRID DISSIPATION

    2 W

    GRID DISSIPATION .. ......... 2.0 WATTS Duty Factor . . ... ...t

  • FREQUENCY. ... ... ... ...,

    3 GHz

    FREQUENCY. ... ... ... ..., 3.0 GIGAHERTZ

  • PULSE DURATIONY

    6 us

    PULSE DURATIONY. . .. ........ 6 usec

  • DUTY FACTORY

    33

    DUTY FACTORY. . . .. ......... .0033

  • PULSE MODULATOR OR PULSE AMPLIFIER DC PLATE CURRENT

    100 mA

    PULSE MODULATOR OR PULSE AMPLIFIER DC PLATE CURRENT ........ 100 MILLIAMPERES

  • SERVICE PLATE DISSIPATION( [1]

    7855 W

    SERVICE PLATE DISSIPATION(7855) .... 100 WATTS

  • SERVICE PLATE DISSIPATION( [2]

    100 W

    SERVICE PLATE DISSIPATION(7855) .... 100 WATTS

  • MAXIMUM RATINGS/ABSOLUTE VALUES GRID DISSIPATION

    1.5 W

    MAXIMUM RATINGS/ABSOLUTE VALUES GRID DISSIPATION .. ....... 1.5 WATTS

  • PULSE DURATION™

    6

    PULSE DURATION™. . .. ... ... 6 ps

  • DC PLATE VOLTAGE [1]

    2500 V

    DC PLATE VOLTAGE ... ........ 2500 VOLTS DUTY FACTORY. . . .......... 0033

  • DC PLATE VOLTAGE [2]

    33 V

    DC PLATE VOLTAGE ... ........ 2500 VOLTS DUTY FACTORY. . . .......... 0033

  • PEAK PLATE VOLTAGE [1]

    3500 V

    PEAK PLATE VOLTAGE . . . .. ..... 3500 VOLTS CUT-OFF MU . ... .cvvv v 60

  • PEAK PLATE VOLTAGE [2]

    60 V

    PEAK PLATE VOLTAGE . . . .. ..... 3500 VOLTS CUT-OFF MU . ... .cvvv v 60

  • DCGRIDVOLTAGE

    -150 V

    DCGRIDVOLTAGE . ... ........ -150 VOLTS

  • INSTANTANEQUS PEAK GRID-CATHODE VOLTAGE

    1

    INSTANTANEQUS PEAK GRID-CATHODE VOLTAGE 1. For application requiring longer pulse duration and/

  • Grid negative to cathode

    -750 V

    Grid negative to cathode ....... -750 VOLTS or higher duty cycle consult the nearest Varian

  • PULSE CATHODE CURRENT

    4.8 A

    PULSE CATHODE CURRENT . . ... .. 4.8 AMPERES duct Manager Eimac-Division of Varian, Salt Lake

  • Heater: Current at [1]

    6 V

    Heater: Current at 6.0 volts . ...... . e e e 0.90 1.05

  • Heater: Current at [2]

    0.9 V

    Heater: Current at 6.0 volts . ...... . e e e 0.90 1.05

  • Heater: Current at [3]

    1.05 V

    Heater: Current at 6.0 volts . ...... . e e e 0.90 1.05

  • Cathode Heating Time . . . . ... v i iii it i nnenn

    60

    Cathode Heating Time . . . . ... v i iii it i nnenn 60 --- sec.

  • Published value

    1

    1. Capacitance values for a cold tube as measured in a special shielded fixture. When the cathode is heated to the

  • proper temperature, the grid-cathode capacitance will increase from the cold value by approximately

    1 pF

    proper temperature, the grid-cathode capacitance will increase from the cold value by approximately 1 pF due to

  • Published value

    5 A

    5 —=——— PEAK GRID CURRENT—-AMPERES

  • PLATE VOLTAGE (V) CURVE #MA

    2376 mA

    PLATE VOLTAGE (V) CURVE #MA-2376

  • PLATE VOLTAGE (V) CURVE #MA

    2377 mA

    PLATE VOLTAGE (V) CURVE #MA-2377

Data set 02

1975 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Heater Current Range

    900 mA to 1.05 A

  • Cathode Heating Time

    60 s

Capacitance

  • Input Capacitance

    6.8 pF

  • Output Capacitance

    0.04 pF

  • Grid-Plate Capacitance

    2 pF

Other

  • Frequency Maximum

    3 GHz

  • Pulse Plate Voltage Maximum

    3500 V

    PlatePulsed

  • Pulse Current Maximum

    4.8 A

    PulseModulator

  • Pulse Duration Maximum

    6 us

  • Duty Factor Maximum

    0.0033

  • Pulse Plate Current Maximum

    3 A

  • Pulse Grid Current Maximum

    1.8 A

  • Typical Pulse Output

    750 W

    Frequency=1.09GHz

Data set 03

1976 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Heater Current Range

    900 mA to 1.05 A

  • Cathode Heating Time

    60 s

Capacitance

  • Input Capacitance

    6.8 pF

  • Output Capacitance

    0.04 pF

  • Grid-Plate Capacitance

    2 pF

Other

  • Frequency Maximum

    3 GHz

  • Pulse Plate Voltage Maximum

    3500 V

    PlatePulsed

  • Pulse Current Maximum

    4.8 A

    PulseModulator

  • Pulse Duration Maximum

    6 us

  • Duty Factor Maximum

    0.0033

  • Pulse Plate Current Maximum

    3 A

  • Pulse Grid Current Maximum

    1.8 A

  • Typical Pulse Output

    750 W

    Frequency=1.09GHz