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Diode (NOT rectifier) ·Diode

K81A

Directly heated noise diode designed as a calibrated standard noise source for metric-wave measurements, with recommended operation to approximately 300 MHz.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
NOVAL
Socket code
B9A
Base pins
9
Nominal heater
1.85 V / 2.5 A

Description

Directly heated noise diode intended as a calibrated standard noise source for metric-wave measurements.

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
NOVAL
Socket code
B9A
Base pins
9
Nominal heater voltage
1.85 V
Nominal heater current
2.5 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

NOVAL - 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

Diode

X-ray radiationInterelectrode capacitances
Max plate voltage
150 V
Max plate dissipation
3 W
Max cathode current
20 mA

Published ratings and characteristics promoted semantically from the approved Philips source.

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

1957 Philips Receiving and Amplifying Tubes

Published operating points and test conditions from this source.

SECTION 1

Diode

Other

  • Maximum Plate Voltage

    150 V

  • Maximum Plate Dissipation

    3 W

  • Maximum Cathode Current

    20 mA

  • Filament Voltage

    1.85 V

  • Filament Current

    2.5 A

  • Anode Voltage

    100 V

  • Anode Current

    15 mA

  • Maximum Filament Voltage

    2 V

  • Maximum Anode Voltage

    150 V

  • Maximum Anode Current

    20 mA

  • Maximum Anode Dissipation

    3 W

Data set 02

1999 Philips E-Z

Published operating points and test conditions from this source.

SECTION 1

Diode

Capacitance

  • Anode-filament capacitance

    2.2 pF

Characteristics

  • Typical anode voltage

    100 V

  • Typical anode current

    15 mA

  • Maximum recommended frequency

    300 MHz

Other

  • Maximum filament voltage

    2 V

  • Maximum anode voltage

    150 V

  • Maximum anode current

    20 mA

  • Maximum anode dissipation

    3 W