7489

Rugged long-life double triode with independent sections for AF and control applications, designed for low catastrophic failure rate, frequent heater switching, and stable cathode performance.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: B9A
Base pins: 9
Nominal heater: 12.6 V / 150 mA

Description

The 7489 is a nine pin all glass construction double triocde with independent sections for use in A.F., and control applicat The use of a special rugged electrode construction manufactured reans of semi-automatic assembly techniques contributes to a low catastrophic failure rate, The cathode sleeve is made of a special alloy to inhibit the growth of cathode interface resistance during long periocds of operation under cut-off conditions and the pure tungsten heater has been designed to withstand frequent heater switching (sec note), In addition, the heater- cathode construction and materials ensure very low levels of The glass base amd envelope strain patterns are tightly controlled

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B9A
Base pins: 9
Nominal heater voltage: 12.6 V
Nominal heater current: 150 mA
Parallel heater voltage: 6.3 V
Parallel heater current: 300 mA
Series capable: Yes

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Transconductance: 0.0022 S
Amplification factor: 17
Max plate voltage: 330 V
Max plate dissipation: 3 W
Max cathode current: 20 mA

Primary electrical section; identical repeated sections compressed where applicable.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Transconductance: 0.0022 S
Amplification factor: 17
Max plate voltage: 330 V
Max plate dissipation: 3 W
Max cathode current: 20 mA

Second physical triode section; electrically identical twin 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

1954 STC Brimar

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

nominal value: heater cathode veoltage 240V r,m.s.: applied voltages
240 V
nominal value: heater cathode veoltage 240V r,m.s.: applied voltages
Voltage (ac or dec) 12.6 6.3 volts
6.3 V
Voltage (ac or dec) 12.6 6.3 volts
Current 0.15 0.3 amps,
300 mA
Current 0.15 0.3 amps,
Maztimun anode dissipation (Fach scCtion) s.cecocecsscess 3.0 watts
3 W
Maztimun anode dissipation (Fach scCtion) s.cecocecsscess 3.0 watts