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

4308B

Directly heated transmitting power triode intended for RF amplifier, oscillator, or modulator service. Manufacturer operating data emphasize radio-frequency power generation, substantial plate loading, and professional transmitter applications.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
LARGE4BAYONET
Base pins
4
Nominal heater
14 V / 6 A

Description

Triode.

Socket description

Large 4-contact bayonet base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
LARGE4BAYONET
Base pins
4
Nominal heater voltage
14 V
Nominal heater current
6 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
Plate resistance
1070 Ω
Transconductance
0.0075 S
Amplification factor
8
Max plate voltage
2250 V
Max plate dissipation
250 W
Max cathode current
325 mA

Ratings and characteristics extracted from 4308B.pdf.

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

1937 Standard Valves

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Total emission

    4 A

  • Grid-anode capacitance

    17.4 pF

  • Grid-filament capacitance

    13.6 pF

  • Anode-filament capacitance

    9.3 pF

Other

  • Maximum direct anode current

    325 mA

  • Maximum direct grid current

    75 mA

  • Maximum frequency for full ratings

    15 MHz

  • Anode voltage at 45 MHz

    750 V

    45MHz

Data set 02

1946 Standard Telephone and Cables

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Constants

    1 A

  • Filament voltage

    14 volts

  • Nominal filament curren

    6 amps

  • Total emission

    4 amps

  • Impedance

    1070 ohms

  • Mutual conductance

    7.5 mA

  • at Vp =

    1500 volts

  • Maximum direct anode voltage

    2250 volts

  • Maximum direct anode curren

    325 mA

  • Maximum direct grid curren

    75 mA

  • Maximum anode dissipation

    250 watts

  • Maximum frequency for above ratings

    -5 Mc

  • Maximum anode voltage for frequency o

    4.5 Mc

  • Direct anode voltage 1,500

    1000 volts

  • Grid bias —155

    -380 volts

  • Direct anode current 135

    210 mA

  • Load impedance 13,000

    3000 ohms

  • Undistorted output 50

    35 watts

  • Direct anode voltage 1,750

    1500 volts

  • Grid bias —215

    -180 volts

  • Direct anode current per valve—Zero signal 30

    25 mA

  • Maximum signal 300

    300 mA

  • Anode dissipation 240

    210 watts

  • Load resistance—anode to anode 5,200

    4280 watts

  • Power output—2 valves 575

    475 watts

  • Recommended power for driving stage 35

    35 watts

  • Direct anode voltage 1,750 1,500 1,250 1,000 1,750

    1500 volts

  • Direct anode current 215 250 300 300 300

    300 mA

  • —460

    -400 volts

  • Anode dissipation 250 250 125 100 175

    150 watts

  • Carrier output 125 125 250 200 350

    300 watts