Western electric 102 f brochure

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102E|

Issue 2
BELL SYSTEM PRACTICES SECTION AB46.052
Transmission Engineering and Data Issue 2
Vacuum Tube Data A T & T Co Standard

Weary/~11 Elect/412

. 102F Vacuum Tube
(Dome)

Classifications-Filamentar-y, voltage amplifier triode

This tube is a redesign of the 102F tube. It includes an improved filament, a new mechanical
design using transverse mica supports and is mounted in a dome type bulb. The electrical char-
acteristics are practically identical with the previous 102F tube which it supersedes.

Applications-Voltage amplifier for voice-frequency telephone repeaters and carrier-frequency

telegraph equipment.
. Detector or modulator.
Dimensions and Connections-The outline diagrams of the tube and base, giving the
1 dimensions and the arrangement of the electrode connections to the base terminals are shown in
Figures 1 and 2.

Base and Mounting-This vacuum tube employs a medium, four-pin bayonet type base
having special contact metal at the ends of the pins. It is suitable for use in a Western Electric
. 100L, 100R, or similar type socket, preferably provided with contact-metal contacts.

The tube may be mounted in either a vertical or horizontal position. If mounted in a hori-
zontal position the plane of the filament, which is indicated in Figure 2, should be vertical. To
assure adequate ventilation the tubes should be mounted with not less than 2% inches between
centers when two or more tubes are used.

Copyright 1939 Western Electric Company, Incorporated

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102F

Average Direct Interelectrode Capacitances

Grid to plate. .. .. ........... .. . .. 5.1 ,upf
Grid to filament . . . ..... . . . . ..... . . 4.0 [inf
Plate to filament. . . .. . ... . ....... .. ... 2.3 ,u,uf

These values are for a based tube without socket.

Filament Rating

Filament current. . . . . . . ........... . . 0.50 ampere, ci.c.
Nominal filament voltage . . . ............... . . 2.1 volts

The filament of this tube is designed to operate on a current basis and should be operated at as
near the rated current as practicable.

The filament resistance of this tube increases slightly during the first 2000 hours of operation.
The voltage given above is the nominal value after the resistance has stabilized.

Characteristics-Typical curves showing plate current as a function of grid voltage for several
values of plate voltage are shown in Figure 3. The grid and plate voltages are measured from the
negative end of the filament. Corresponding amplification factor, plate resistance and transcon-
ductance characteristics are given in Figures 4, 5 and 6 respectively. Plate current as a function
of plate voltage for several values of grid voltage is shown in Figure 7.

Operating Conditions and Output-Permissible operating plate and grid voltages are
included within the area, ABCD in Figure 3. A number of recommended and maximum operating
conditions and the corresponding values of amplification factor, plate resistance, transconductance
and performance data are given in the table below. Recommended conditions or others of no
greater severity should be selected in preference to maximum conditions wherever possible. The
life of the tube at maximum operating conditions may be shorter than at less severe conditions.

The performance data shown include the fundamental output voltage in peak volts and the
second and third harmonic levels in db below the fundamental for values of load resistance equal
to the plate resistance and for load resistances of 100,000 and 300,000 ohms. The peak value of
the sinusoidal input voltage Egm, which gives the indicated output Em, and harmonic levels Fgm
and Fgm, in each case is numerically equal to the grid bias. For a smaller input voltage Eg, the
approximate levels may be computed from the following relations:

E~
Ep = 13,... E;

F. = F2111 + 201090?

F3

E
Fm+401g in
3 010E;

)Iicrophonie Noise

For a plate voltage of 130 volts, a grid bias of - 1.5 volts and a load resistance of 100,000 ohms,
the mean microphonic output level of this tube, measured in a laboratory reference test set is 33 db
below 1 volt. The range oflevels ofindividual tubes extends from 25 to 41 db below 1 volt. Since
microphonic noise output depends on the type and intensity of the mechanical disturbance which
produces it. the ValJES given here are useful chiefly for comparison with the levels of other types
of tubes which have been tested in the same way.

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