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Power - Triode ·Triode

3B850A

Power triode intended for both audio-frequency and radio-frequency service. Low plate resistance, 100 W plate dissipation, and 1.25 kV plate capability provide substantial medium-power performance for output, modulator, and transmitter applications.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
LARGE4BAYONET
Base pins
4
Nominal heater
10 V / 3.25 A

Description

Power triode for audio and radio-frequency service.

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
10 V
Nominal heater current
3.25 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
3000 Ω
Amplification factor
12
Max plate voltage
1250 V
Max plate dissipation
100 W
Max cathode current
150 mA

Published triode ratings/characteristics promoted from the approved datasheet.

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

1946 Standard Telephone and Cables

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Grid-anode capacitance

    13 pF

    Direct inter-electrode capacitance

  • Grid-filament capacitance

    6.5 pF

    Direct inter-electrode capacitance

  • Anode-filament capacitance

    4 pF

    Direct inter-electrode capacitance

Data set 02

1947 Standard Valves

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Maximum frequency at full rating

    6 MHz