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7498

Rugged seven-pin all-glass pentode engineered for low catastrophic failure, long cutoff operation, frequent heater switching, and low heater-cathode leakage. Its construction emphasizes reliability and long-term stability in demanding electronic service.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 300 mA

Description

The 7498 is a seven pin all glass constructicn pentode for use in The use of » special rugzed electrode construction manufactured by neans of seni-automatic assenbly techniques contributes to a low catastrophic foilure rate, The cathode slceve is made of a special allcy to inhibit the growth of cathole interface rcsistance during long pericds of operation under cut=ofT conditiona and the purc tungsten heater has been designed to withstend frequent heater switching (sce note), In addition the heater— cathode construction and materials ensure very low levels of lealiage The glass base and envelope strain patterns are tightly controlled during nanufacture to prevent ¢lass failures durdng life. Special

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B7G
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 300 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

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Max plate voltage: 300 V
Max plate dissipation: 3 W

Primary electrical section; identical repeated sections compressed where applicable.

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

1954 STC Brimar

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

Voltage (ac or de) 6.3 volts
6.3 V
Voltage (ac or de) 6.3 volts
Heater negative with respect tc cathode ............. 150 volts
150 V
Heater negative with respect tc cathode ............. 150 volts
Ancde current 7.5 9,85 12,2 mA
12.2 mA
Ancde current 7.5 9,85 12,2 mA
Mutual conductance 6,0 7.62 9.25 mA/V
9.25 mA
Mutual conductance 6,0 7.62 9.25 mA/V
Ancde current at Vg = « 8V 100 ua
8 V
Ancde current at Vg = « 8V 100 ua

Other

Maxirum anode voltage (In=0) .......... e e . 550 volts
550 V
Maxirum anode voltage (In=0) .......... e e . 550 volts
Maxirmum anode voltage v.vevveinrienrenanns teereresenans 300 volts
300 V
Maxirmum anode voltage v.vevveinrienrenanns teereresenans 300 volts
Maxirmum anode dissipation .........cevevveen. desesseenas 3.0 watts
3 W
Maxirmum anode dissipation .........cevevveen. desesseenas 3.0 watts
Maxirum screen voltage (Ig2=0) € eeeitiarreeeeaaaa cesee 450 volta
450 V
Maxirum screen voltage (Ig2=0) € eeeitiarreeeeaaaa cesee 450 volta