7490

Heavy-duty double triode with independent sections, high plate-voltage and dissipation ratings, and substantial heater-cathode insulation for demanding amplifier or control applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: -
Socket code: B9A
Base pins: 9
Nominal heater: 12.6 V / 300 mA

Description

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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: 300 mA
Parallel heater voltage: 6.3 V
Parallel heater current: 600 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: 0.00235 S
Amplification factor: 32
Max plate voltage: 200 V
Max plate dissipation: 5 W

Primary electrical section; identical repeated sections compressed where applicable.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Transconductance: 0.00235 S
Amplification factor: 32
Max plate voltage: 200 V
Max plate dissipation: 5 W

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 voltage of 240V r.n.s: applied voltages
240 V
nominal value: heater—cathode voltage of 240V r.n.s: applied voltages
Voltage (ac or ac) 12.5 6.3 volts
6.3 V
Voltage (ac or ac) 12.5 6.3 volts
Current 0.3 C.6 amps.
6 A
Current 0.3 C.6 amps.
Heater positive with respect to cathode e...ooe.. 200 volts
200 V
Heater positive with respect to cathode e...ooe.. 200 volts
Anode current at Vg = -10V 500 pA
-10 V
Anode current at Vg = -10V 500 pA

Other

Maximum snode voltage {(Ia=0) vesccvocosacscsasacssss 550 vOlts
550 V
Maximum snode voltage {(Ia=0) vesccvocosacscsasacssss 550 vOlts
Maximun anode dissipation (Bach section) sesssssseess 5.0 watts
5 W
Maximun anode dissipation (Bach section) sesssssseess 5.0 watts