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Power - Beam (NOT sweep) ·BeamPower

KT77

Audio-frequency beam pentode explicitly designed for beam-power output service in high-quality power-amplifier stages.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
IO
Base pins
8
Nominal heater
6.3 V / 1.4 A

Description

The source identifies this device as KT77 a. f. beam pentode. It also specifies beam-power output service.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
IO
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
1.4 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

Beam Power

X-ray radiationInterelectrode capacitances
Plate resistance
23000 Ω
Transconductance
0.0105 S
Amplification factor
11.5
Max plate voltage
850 V
Max screen voltage
650 V
Max plate dissipation
32 W
Max screen dissipation
6 W
Max cathode current
200 mA

A.F. beam pentode.

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

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

  • A beam tetrode with an absolute maximum anode dissipation rating of

    32 W

    Published datasheet value; semantic OCR text extraction.

Data set 02

199X JJ

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

  • Typical Plate Voltage

    250 V

  • Typical Screen Voltage

    250 V

  • TypicalControlGridVoltage

    -15 V

  • Typical Plate Current

    100 mA

  • Typical Screen Current

    10 mA

  • MaximumCombinedPlateScreenDissipation

    28 W

Characteristic

  • GridCapacitance

    16.5 pF

  • Plate Capacitance

    9 pF

  • PlateGridCapacitance

    1 pF

Data set 03

2026 Genalex Rebrand

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Characteristic

  • Plate Current

    80 to 130 mA

    Plate 250 V; screen 250 V; grid -11 V

  • Transconductance

    8500 to 14000 µS

    Plate 250 V; screen 250 V; grid -11 V

Other

  • Power Output

    7 W

    Plate 250 V; screen 250 V; load 2.0 kohm; ClassA;OneTube

Data set 04

2026 JJ Electronic

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

  • Uf

    6.3 V

    Published value

  • If

    1.4 A

    Published value

Characteristics

  • Ua

    250 V

    Published value

  • Ug2

    250 V

    Published value

  • Ug1

    -13.5 V

    Published value

  • Ia

    100 mA

    Published value

  • Ig2

    10 mA

    Published value

  • S

    10500 µS

    Published value

  • µ

    11.5

    Published value

Capacitance

  • Cg1

    16.5 pF

    Published value

  • Ca

    9 pF

    Published value

  • Ca/g1

    1 pF

    Published value