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Voltage - Triode (single) ·Triode

4065

Directly heated subminiature electrometer triode designed for precision measurement and amplification of extremely small electrical currents.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B8D
Base pins
-
Nominal heater
1.25 V / 13 mA

Description

Directly heated subminiature electrometer triode for very-low-current measurement.

Socket description

Subminiature 8-lead

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B8D
Base pins
-
Nominal heater voltage
1.25 V
Nominal heater current
13 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

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
25000 Ω
Transconductance
0.00008 S
Amplification factor
2
Max plate voltage
25 V

Philips directly heated subminiature electrometer triode. Published gm 80 µA/V (0.00008 S) and mu 2; promoted rp 25000 ohms is calculated as mu/gm, not independently specified. Absolute maximum anode voltage 25 V and anode current 250 µA (not an explicitly stated cathode-current limit). Filament 1.25 V DC, 13 mA, allowable 1.1–1.5 V. Typical Va 9 V, Ia 100 µA, Vg -2.5 V; grid current typical 8.5e-14 A, limit 1.25e-13 A in darkness. Apply filament voltage before anode voltage.

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

Triode

Characteristic

  • HeaterOrFilamentVoltage

    1.25 V

  • HeaterOrFilamentCurrent

    13 mA

  • GridCurrentTypical

    0.000000000085 mA

    Electrometer

  • Anode current

    250 µA

    Absolute maximum anode current

  • Grid Current

    0.000000000125 mA

    Maximum specified grid current magnitude, measured in darkness

  • Filament voltage

    1.1 to 1.5 V

    Nominal filament voltage 1.25 V DC; absolute limits 1.1–1.5 V

  • Grid Current

    0.000000000085 mA

    Typical grid current magnitude in darkness at normal operating conditions

Other

  • Plate Voltage

    9 V

    Electrometer

  • Plate Current

    100 uA

    Electrometer

Data set 02

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Heating : direct by D.C. Ve

    1.25 V

    Heating : direct by D.C. Ve = 1,25 V

  • Chauffage: direct par C.C. I

    13 mA

    Chauffage: direct par C.C. I = 13 mA

  • 2 "Crossover point"(measured at Vp

    Crossover-point explanatory note (English): measured at Va=9 V; grid current reverses polarity.

    2 "Crossover point"(measured at Vp= 9 V)is the point at

  • "Point de croissement” (mesuré & Vo

    Crossover-point explanatory note (French), same definition as English.

    "Point de croissement” (mesuré & Vo =9 V), c'est le

  • v{Jbergangspunkt” (gemessen bei Vo

    Crossover-point explanatory note (German), same definition as English.

    v{Jbergangspunkt” (gemessen bei Vo = 9 V), dass heisst

  • Control Grid Voltage

    -3.75 to -2 V

    Typical grid bias -2.5 V; published range -3.75 to -2.0 V at Va=9 V, Ia=100 µA

  • Vgd) = -1,3

    -1.6 to -1.3 V

    Grid-current crossover point measured at Va=9 V; approximate -1.3 V, limit -1.6 V

  • 3 "Crossover point" (measured at Va

    Crossover-point explanatory note (English), duplicate from alternate Philips sheet.

    3 "Crossover point" (measured at Va = 9 V) is the point

  • "Point ge croissement" (mesuré & Va

    Crossover-point explanatory note (French), duplicate translation.

    "Point ge croissement" (mesuré & Va = 9 V), c'est le

  • "Ubergangspunkt" (gemessen bei Va

    Crossover-point explanatory note (German), duplicate translation.

    "Ubergangspunkt" (gemessen bei Va = 9 V), das heisst

  • Filament voltage

    1.1 to 1.5 V

    Philips filament voltage absolute limits; original OCR incorrectly labeled as grid voltage