< Table of Contents - Index - Next > CROSS-REFERENCE DATA
The following tube characteristic cross-reference and equivalence charts
are included to help guide the user in selecting substitutes for tubes
listed in this Manual . They also enable the designer to use tubes that
are not included, but have identical characteristics.Where several similar tubes differing only in filament voltage are
available, standard practice in these lists has been to make the principal
listing in the 6- or the 7- tube series. Tubes bearing codes starting with
the numbers 3, 4, 5, 9, 12, 19, 25, etc., should be checked under the
corresponding 6-series. The 14-series should be checked under the 7-series.Tube classification techniques have always been a problem. The
setting up of a simple standard means of identifying the characteristics
of a tube by a number and letter combination has been tried several
times in this country. In every case the standardizing nomenclature has
fallen into disuse. The best identifying system so far found by the writer
appears to be one used by several European organizations, typically
Mullard, Telefunken, and others. For that reason, a slightly modified
version of the Continental system has been prepared for use in tube
classification in this Manual . The defining table, with additions made
to improve its utility with the present application, follows.The nomenclature used consists of a series of identifying letters fol-
lowed by two or more numbers. The first letter of the series is used to
indicate the filament or heater voltage or current. (Additions to the
standard table are followed by the symbol pi.) For the first letter:A 4.0-volt filament H 150-ma heaterThe series of letters following the first letter are used to identify the
C 200-ma heater J 26-volt heater
D 0.5- to 1.5-volt filament K 2.0-volt filament
E 6.3-volt heater P 300-ma heater
(also used with 6.3-/12.6-volt tubes)
G 5.0-volt heater U 100-ma heater
types of structures, i.e., diodes, triodes, etc., that comprise the active
elements of the tube. The revised list as used in this Manual is as follows:A single diode M electron-beam indicatorSeveral of the above letters may have to be used with a tube to describe
B double diode N thyratron
C triode P secondary-emission tube (used
D output triode only as third letter)
E tetrode Q nonode
F voltage-amplifier pentode S dual-control pentode (pi)
FR remote-cutoff pentode (pi) X full-wave gas rectifier
H hexode Y haft-wave rectifier
K heptode or octode Z full-wave rectifier
L output pentode
completely the tube structure. For example, the twin-triode 6SN7
25
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Copyright 2008 for Phyllis K. Pullen, M.D.,
by Robert J. Legg