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25W6GT

Beam-power amplifier specifically designed as a television vertical-scanning output tube, with published operating data also covering triode-connected operation.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7AC
Socket code: IO
Base pins: 7
Nominal heater: 25 V / 300 mA

Description

The 25W6GT is a beam pentode power amplifier designed specifically as a vertical-scanning output tube in television receivers and also has published triode-connected characteristics.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7AC
Socket code: IO
Base pins: 7
Nominal heater voltage: 25 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7AC - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1Pin 1	—	NC	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN2Pin 2	—	H — Heater	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN3Pin 3	A	P — Plate (Anode)	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN4Pin 4	A	G2 — Screen Grid	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN5Pin 5	A	G1 — Control Grid	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN7Pin 7	—	H — Heater	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN8Pin 8	A	BP — Beam-Forming PlateGroup AC8	Verified 12L6GT/25L6GT manufacturer basing, 7AC
PIN8Pin 8	A	K — CathodeGroup AC8	Verified 12L6GT/25L6GT manufacturer basing, 7AC

Section ratings

1 physical section, each with unique specifications.

Section 1

Beam Power

X-ray radiationInterelectrode capacitances

Plate resistance: 28000 Ω
Transconductance: 0.008 S
Max plate voltage: 300 V
Max screen voltage: 150 V
Max plate dissipation: 10 W
Max screen dissipation: 1.25 W
Max cathode current: 60 mA

Class-A promoted values use the 200-V operating column; alternate operating points and triode-connection data are preserved as 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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Maximum plate voltage
300 V
Published handbook rating
Maximum screen voltage
150 V
Published handbook rating
Plate voltage
200 V
ClassA
Screen voltage
125 V
ClassA
Control-grid bias
46 V
ClassA
Plate current
46 mA
ClassA
Screen current
2.2 mA
ClassA
Load resistance
4000 ohm
ClassA
Power output
3.8 W
ClassA
Triode-connected plate voltage
225 V
TriodeConnection VerticalDeflection
Triode-connected control-grid bias
30 V
TriodeConnection VerticalDeflection
Triode-connected plate current
22 mA
TriodeConnection VerticalDeflection
Maximum positive pulse plate voltage
1200 V
VerticalDeflection
Maximum plate dissipation
7.5 W
VerticalDeflection
Maximum DC cathode current
40 mA
VerticalDeflection
Alternate pentode plate voltage
110 V
PentodeConnection ClassA
Alternate pentode control-grid bias
7.5 V
PentodeConnection ClassA
Alternate pentode plate current
49 mA
PentodeConnection ClassA
Alternate pentode screen current
4 mA
PentodeConnection ClassA
Alternate pentode load resistance
2000 ohm
PentodeConnection ClassA
Alternate pentode power output
2.1 W
PentodeConnection ClassA

Characteristic

Plate resistance
28000 ohm
Published handbook characteristic
Transconductance
8000 µS
Published handbook characteristic
Heater/filament voltage
25 V
Published heater/filament rating
Heater/filament current
300 mA
Published heater/filament rating
Triode-connected plate resistance
1600 ohm
TriodeConnection
Triode-connected transconductance
3800 µS
TriodeConnection
Alternate pentode plate resistance
13000 ohm
PentodeConnection
Alternate pentode transconductance
8000 µS
PentodeConnection

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater voltage
25 V
Nominal
Heater current
300 mA
Nominal
Maximum peak positive pulse plate voltage
1200 V
VerticalDeflection
Maximum peak negative grid 1 voltage
-250 V
VerticalDeflection
Maximum peak cathode current
140 mA
VerticalDeflection
Plate voltage
110 V
ClassA; OperatingPoint1
Plate voltage
200 V
ClassA; OperatingPoint2
Screen voltage
110 V
ClassA; OperatingPoint1
Screen voltage
125 V
ClassA; OperatingPoint2
Load resistance
2000 ohm
ClassA; OperatingPoint1
Load resistance
4000 ohm
ClassA; OperatingPoint2
Power output
2.1 W
ClassA; OperatingPoint1
Power output
3.8 W
ClassA; OperatingPoint2

Characteristic

Plate resistance
13000 ohm
ClassA; OperatingPoint1
Plate resistance
28000 ohm
ClassA; OperatingPoint2
Transconductance
8000 uS
ClassA; OperatingPoint1
Transconductance
8000 uS
ClassA; OperatingPoint2
Amplification factor
6.2
TriodeConnection
Plate resistance
1600 ohm
TriodeConnection
Transconductance
3800 uS
TriodeConnection

Capacitance

Grid 1 to plate
0.5 pF
Direct interelectrode capacitance
Input capacitance
15 pF
Direct interelectrode capacitance
Output capacitance
9 pF
Direct interelectrode capacitance

Data set 03

1966 Tung Sol Electronic Tubes 3 of 4

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Maximum plate voltage
300 V
WholeTube
Maximum screen voltage
150 V
WholeTube
Maximum plate dissipation
10 W
WholeTube
Maximum screen dissipation
1.25 W
WholeTube
Plate voltage
110 V
ClassA1
Screen voltage
110 V
ClassA1
Plate resistance
13000 ohm
ClassA1
Transconductance
8000 µS
ClassA1
Power output
2.1 W
ClassA1

Data set 04

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Characteristic

Plate Resistance
13000 ohm
ClassA;Ep=110V
Plate Resistance Triode Connection
1600 ohm
TriodeConnection
Transconductance Triode Connection
3800 uS
TriodeConnection
Amplification Factor Triode Connection
6.2
TriodeConnection

Other

Plate Voltage
110 V
ClassA
Screen Voltage
110 V
ClassA
Power Output
2.1 W
ClassA