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Specialized - Gauge Tube ·Gauge

7675

Bayard-Alpert inverted-geometry ionization gauge designed to measure ultra-high-vacuum pressures down to approximately 10^-10 mm Hg.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
-
Base pins
-
Nominal heater
2 V / -

Description

Westinghouse July 1, 1961 LOW PRESSURE I0ON GAUGE TUBE TYPE 7675 The 7675 is an ionization type of vacuum-gauge tube for measurement of gas pressures as low as 10— 10 mm of mercury. The tube has a hard glass bulb with a one-halfinch diameter tubulation. The 7675 employs on electrode structure having a minimum of metal surface with the result that the tube is easily out-gassed. The 7675 is a triode of the Bayard-Alpert inverted geometry design having twe tungsten filaments, one of which is a spare, The grid structure is operated at a positive potential with respect to the filoment while the ion collector is at a negative potential. Electrons are accelerated from the filament to the grid; they bombard and ionize gas molecules, and the resultant positive ions are attracted to the collector. The ratio of the collector current (positive ion current) to the grid current is proportional to the gas pressure, ELECTRICAL: Filament Type (Note 1}. .. .. .. .o v i iu v Tungsten Operating Filament V

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
-
Nominal heater voltage
2 V
Nominal heater current
-
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

Gauge

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Source-derived physical/electrical 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

1947 Westinghouse

Published operating points and test conditions from this source.

SECTION 1

Gauge

Other

  • The

    10

    The 7675 is an ionization type of vacuum-gauge tube for measurement of gas pressures as low as 10— 10 mm of

  • Operating Filament Voltage (Approx.}

    7

    Operating Filament Voltage (Approx.}. . .. .. .. 7 ac or dc Volts

  • QOperating Filament Current . .. .. .. o

    8

    QOperating Filament Current . .. .. .. o0 o0 2.5 £ 8% Amperes

  • lon Collector Voltage . . . . ... .. ... ... =

    100

    . lon Collector Voltage . . . . ... .. ... ... =100 max. Velts

  • Grid Voltage. . .. .. ... e e e e

    500

    Grid Voltage. . .. .. ... e e e e +500 max. Volts

  • ——

    0.001

    —— 2" — Gos Pressure . . ... .... Ce e e 0.001 max. mm Mg

  • 1 iy Filament Voltage (Note 2} . . . ... .. .... 10 max. Vol

    10

    1 iy Filament Voltage (Note 2} . . . ... .. .... 10 max. Volis

  • l_fi lon Collector Yoltage . . .. oo v v o vt i i e s =

    30

    :l_fi lon Collector Yoltage . . .. oo v v o vt i i e s =30 Volts

  • Grid Yoltage. . . . . .. et e e e

    150

    Grid Yoltage. . . . . .. et e e e +150 Volts

  • Sensitivity . . ... oo .. e v e e e

    5

    Sensitivity . . ... oo .. e v e e e 140a./10=5 mm Hg

  • Grid Voltage. . . .. ... v oo v L e

    500

    Grid Voltage. . . .. ... v oo v L e +500 mox. Volis

  • Porallel .. ,

    10

    Porallel .. ,........ 10 max. Volts

  • —r —

    100

    —r — 1 Grid & Collector Power. - . . .. .0 cuv v 100 mox. Watts

  • hos been reduced to

    0.001

    hos been reduced to 0.001 mm of mercury. The power-supply

  • may be present. A grid voltoge of

    150

    may be present. A grid voltoge of 150 volts is sufficient, ond

  • Outgassing of metal ond glass parts con be occomplishod con- The second supply circuit, Figure

    3

    Outgassing of metal ond glass parts con be occomplishod con- The second supply circuit, Figure 3 provides continuous regulation

  • colloctor should net excesd

    500

    colloctor should net excesd +500 volts and moximum outgas power temperature is reguloted by o varying impedonce In series with the

  • is

    100

    is 100 watts. DC supply is recommendod for outgassing, although primary of the filament transformer. This series impedance is the

  • Resistor value in ohms P, ~

    115

    Resistor value in ohms P, ~ 115voltpilet lomp, green

  • RLa ~

    6.3

    RLa ~ 115-volt relay T — Transformer; 110v primary; 6.3v, la. secondary

  • P

    115

    P1 — 115-volt pilot lomp, red

  • Resistor value in ohms T — Stancor PMB

    12

    Resistor value in ohms T — Stancor PMB412 or equivalent

  • Resistors are

    8412

    Resistors are 1/2 watt except as specifiad, T, — Stancor PM-8412 or equivalent

Characteristic

  • slon current is adjusted by increasing the filament voltage until the voltage potenticl drop across

    6

    slon current is adjusted by increasing the filament voltage until the voltage potenticl drop across the plate laed resistance of the 6AUS.