7494

Special-purpose rugged double triode engineered for reliable long-life operation in demanding electronic equipment, with construction intended to reduce catastrophic failures and maintain stable performance.

Directly heatedCold cathodeCommon cathodeDissimilar

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

Description

The 7494 is a nine pin 211 glass construction double triode with independent sections for use in AJF. and control applications. The use of a special rugged electrode construction manufactured by means of semi-automatic assembly techniques contributes to 2 low catastrophic failure rate. The cathode sleeve is made of a special alloy to inhibit the growth of cathode interface resistance during long periods of omeration under cut~off conditions and the pure tungsten heater has been designed to withstand frequent heater switching (see note). In addition, the heater-cathode construction and materials ensure very low levels of The glass base and 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

Plate resistance: 59000 Ω
Transconductance: 0.0016 S
Amplification factor: 95
Max plate voltage: 330 V
Max plate dissipation: 1.1 W
Max cathode current: 20 mA

Primary electrical section; identical repeated sections compressed where applicable.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 59000 Ω
Transconductance: 0.0016 S
Amplification factor: 95
Max plate voltage: 330 V
Max plate dissipation: 1.1 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 voltage 240V r.n.s: applied voltages
240 V
nominal value: heater cathode voltage 240V r.n.s: applied voltages
Voltage (ac or dc) 12,6 6.3 volts
6.3 V
Voltage (ac or dc) 12,6 6.3 volts
Heater positive with respect to cathode sevceveows. 200 volts
200 V
Heater positive with respect to cathode sevceveows. 200 volts
Moxximum anode vOliagC secesesscconssasosoascssvasssssanss 330 VOlta
330 V
Moxximum anode vOliagC secesesscconssasosoascssvasssssanss 330 VOlta
inode current at Vg = ~5V. 35 uA
5 V
inode current at Vg = ~5V. 35 uA

Other

Maximum cathode current (Bach 8ection) cevesocssecssssss 20 mA
20 mA
Maximum cathode current (Bach 8ection) cevesocssecssssss 20 mA
Maximum anode voltage (Io50) cocevoseossassssscacsaasoes 550 vOLts
550 V
Maximum anode voltage (Io50) cocevoseossassssscacsaasoes 550 vOLts
Maximun snode dissipation (Dech scction) ceeceeseccsesse 1.1 watts
1.1 W
Maximun snode dissipation (Dech scction) ceeceeseccsesse 1.1 watts