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Power - Pentode (NOT beam) ·Diode-Diode-Pentode

UBL21

Twin-diode/high-sensitivity power-pentode combination for detector and audio output in AC/DC receivers.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 3
Base: -
Socket code: B8G
Base pins: 8
Nominal heater: 55 V / 100 mA

Description

High-sensitivity output pentode combined with twin diodes for DC/AC mains-operated receivers.

Socket description

Loctal 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B8G
Base pins: 8
Nominal heater voltage: 55 V
Nominal heater current: 100 mA
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

3 physical sections, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 25000 Ω
Transconductance: 0.008 S
Max plate voltage: 250 V
Max screen voltage: 250 V
Max plate dissipation: 9 W
Max screen dissipation: 1.5 W
Max cathode current: 75 mA

Published ratings and characteristics promoted from the approved source.

Section 2

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Representative section for two diode systems sharing the common cathode.

Section 3

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

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

1951 Mullard Valve and Service Manual

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate Voltage
180 V
ClassA,PentodeSection
Plate Current
61 mA
ClassA,PentodeSection
Screen Voltage
180 V
ClassA,PentodeSection
Power Output
4.5 W
ClassA,PentodeSection

Characteristic

Transconductance
9000 µS
PentodeSection

Data set 02

1957 Philips Receiving and Amplifying Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Application

Application
Audio output

SECTION 2

Diode

Application

Application
Signal detection

Data set 03

195X Tesla

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Plate Current
55 mA
Plate 200 V; Screen 200 V; Grid -13 V

Other

Load Resistance
3500 ohm
ClassA;OneTube;Plate 200 V;Screen 200 V

Data set 04

1967 Mullard Receiving Tubes for Maintenance

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

I. 32.5 61
55 mA
Published in approved UBL21.pdf target datasheet; Section1
Ig2 5.5 10
9.5 mA
Published in approved UBL21.pdf target datasheet; Section1
gm 7.5 9.0
8 mA
Published in approved UBL21.pdf target datasheet; Section1
V1n(r.m.s.) (Pout=
50 mW
Published in approved UBL21.pdf target datasheet; Section1
Ik max
75 mA
Published in approved UBL21.pdf target datasheet; Section1
B
8 G
Published in approved UBL21.pdf target datasheet; Section1

SECTION 2

Diode

Other

I. 32.5 61
55 mA
Published in approved UBL21.pdf target datasheet; Section2
Ig2 5.5 10
9.5 mA
Published in approved UBL21.pdf target datasheet; Section2
gm 7.5 9.0
8 mA
Published in approved UBL21.pdf target datasheet; Section2
V1n(r.m.s.) (Pout=
50 mW
Published in approved UBL21.pdf target datasheet; Section2
Ik max
75 mA
Published in approved UBL21.pdf target datasheet; Section2
B
8 G
Published in approved UBL21.pdf target datasheet; Section2

Data set 05

1999 Philips E-Z

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Heater voltage
55 V
SeriesHeater