Varistors; resistors; variable resistors; metal (zinc) oxide varistors
Active· CBP ruling HQ 084651· Issued 1989-08-02
Ruling text
HQ 084651
August 2, 1989
CLA-2 CO:R:C:G 084651 KK
CATEGORY: Classification
TARIFF NO.: 8533.40.00, HTSUS
Peter Buck Feller
Attorney-at-Law
McKenna, Conner & Cuneo
1575 Eye Street, N.W.
Washington, D.C. 20005
RE: Varistors; resistors; variable resistors;
metal (zinc) oxide varistors
Dear Mr. Feller:
In a letter dated May 23, 1989, you request a binding ruling
on behalf of the Harris Corporation regarding the tariff
classification of zinc oxide varistors under the Harmonized
Tariff Schedule of the United States Annotated (HTSUSA). Our
reply follows.
FACTS:
The subject articles are zinc oxide varistors (known as GE-
MOV varistors), imported from Ireland by the Harris Corporation.
These devices are two-terminal, voltage dependent resistors
(VDR's), that exhibit symmetrical, non-linear, voltage-current
characteristics. They are used, in large part, for protecting
electronic components against voltage surges.
ISSUE:
Whether the subject merchandise is properly classifiable in
subheading 8533.40.00, HTSUS, which provides for "[e]lectrical
resistors . . . [o]ther variable resistors;" or in subheading
8541.10.00, HTSUS, which provides for "[d]iodes, transistors and
similar semiconductor devices . . . [d]iodes;" or in subheading
8541.50.00, HTSUS, which provides for [d]iodes, transistors and
similar semiconductor devices . . . [o]ther semiconductor
devices."
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LAW AND ANALYSIS:
In our ruling of April 26, 1988 (081728), we stated that the
"varistors at issue would not be classified as 'diodes' . . .
since according to the relevant literature, they are not 'two
terminal devices with a single p n junction,' as required for
classification under the HTSUS . . . as a 'diode'." In so
ruling, we cited the Explanatory Notes to heading 8541, HTSUS,
which define "diodes" as "two terminal devices with a single p n
junction."
Importer contends that insofar as the Explanatory Notes for
heading 8541, HTSUS, define "diodes" as "two terminal devices
with a single p n junction," such language should not be
exclusory -- i.e., to exclude all multiple junction diodes from
heading 8541, HTSUS, would defeat the statutory intent of the
same. Assuming arguendo that the Explanatory Notes definition of
"diodes" should not be interpreted so as to exclude all multiple
junction diodes from heading 8541, HTSUS, the subject varistors
would only be classifiable in heading 8541 as "diodes" if, of
course, they fall within the terms of that heading. (See HTSUS,
General Rule of Interpretation 1.)
In this regard, while there exist a number of similarities
between "diodes" and "varistors" -- to wit, both are two terminal
semiconductor devices that exhibit non-linear voltage-current
characteristics -- the terms are not synonymous. In "Theory of
Varistor Electronic Properties," Jules Levine discusses varistors
in general, and GE-MOV varistors in particular. In that article,
he states:
In the 1920's a sintered semiconducting powder device was
developed, which exhibited a striking nonlinearity between
current and voltage. This device was called a varistor
. . . When the voltage was reversed, the current also
reversed in a symmetric way about zero current and zero
voltage. The dependence of the current or the voltage on
temperature was very small. (Other non-powder varistors
were developed at the time, whose current voltage
dependencies were asymmetric, but these are now called
solid-state rectifiers or diodes . . . ) (J. Levine, "Theory
of Varistor Electronic Properties," CRC Critical Reviews in
Solid State Services, November 1975.)
Not all of the relevant technical literature draws precisely
this distinction. Most sources divide "varistors" into two
groups: (1) symmetrical; and (2) nonsymmetrical. For example,
the IEEE Standard Dictionary of Electrical and Electronics Terms
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states that "[v]aristors may be divided into two groups,
symmetrical and nonsymmetrical." (See The Institute of
Electrical and Electronics Engineers, Inc. (F. Jay ed.), IEEE
Standard Dictionary of Electrical and Electronics Terms, Third
Edition, at 996 (1984); and J. Shive, The Properties, Physics and
Design of Semiconductor Devices, Van Nostrand Company Inc., at 5
(1959).)
According to these and other sources, "diodes" constitute a
subgroup of nonsymmetrical varistors. In effect, a diode is "a
two-electrode semiconductor device having an asymmetrical
voltage-current characteristic." Put differently, a diode allows
"electric current to flow . . . in one and only one direction."
(See respectively, D. Considine, P.E., ed., Van Nostrand's
Scientific Encyclopedia, Seventh Edition, at 914 (1989); and M.
Weik, Standard Dictionary of Computers and Information
Processing, Revised Second Edition, at 128 (1977).)
Since GE-MOV varistors display a symmetrical response to
electricity -- i.e., they can "carry constant current independent
of the voltage drop across it" -- they are excluded from the
"diode" family. In fact, in a General Electric Selector Guide
published in 1985, GE-MOV varistors are described as "voltage
dependent, symmetrical, metal oxide semiconductor devices." (See
respectively, M. Weik, supra, at 373 and General Electric
Company, "GE-MOV Metal Oxide Varistors," (Transient Voltage
Suppression Devices - Selector Guide), No. 600.60, 3/85.)
Importer also contends that insofar as GE-MOV varistors may
not be classifiable in heading 8541, HTSUS, as "diodes," they are
classifiable in the same heading as "similar semiconductor
devices." In support of this view, importer cites Note 5 to
Chapter 85, which states:
[f]or the classification of the articles defined in this
note, headings 8541 and 8542 shall take precedence over any
other heading in the tariff schedule which might cover them
by reference to, in particular, their function.
Importer correctly points out that if the subject
merchandise falls within the tariff schedule definition of
"similar semiconductor devices," then the same would be properly
classifiable in heading 8541, HTSUS. However, in order to
determine whether a given device that falls within the vast
universe of "semiconductor devices," also falls within the tariff
schedule heading 8541 which provides for "similar semiconductor
devices," reference must be made to the Explanatory Notes which
set forth what does and what does not constitute "similar
semiconductor devices."
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In this regard, the Explanatory Notes to heading 8541,
HTSUS, at 1397-1398 state:
The "similar" devices referred to here are semiconductor
devices whose operation depends on variations in resistivity on
the application of an electrical field.
They include:
(1) Thyristors . . .
(2) Triacs . . .
(3) Diacs . . .
(4) Varactors . . .
(5) Field effect devices . . .
(6) Gunn effect devices . . .
However, this group does not include semiconductor devices
which differ from those described above . . . such as non-
linear semiconductor resistors ( . . . varistors . . . etc.)
(heading 85.33). (Emphasis is in the original.)
If the above language is to have any meaning at all, it
means that heading 8541, HTSUS, does not include varistors of
heading 8533, HTSUS -- i.e., varistors/VDR's described in
Explanatory Note (A)(5) to heading 8533, HTSUS, at 1386. In
effect, the word "group" in the above cited Explanatory Note
refers to "similar semiconductor devices." Excluded from this
"group" are devices such as "non-linear semiconductor resistors
. . . varistors [of] (heading 8533)" --i.e., "(varistors/VDR)."
As already stated, in literature published by the General
Electric Company in 1985 -- the Company whose wholly owned
subsidiary originally manufactured GE-MOV varistors and on whose
behalf our ruling of April 26, 1988 (081728), was issued --
"General Electric Metal Oxide Varistors" are described as
"[v]oltage dependent, symmetrical, metal oxide semiconductor
devices." This description, which accurately describes the
subject merchandise, is entirely consistent with the merchandise
description in heading 8533, HTSUS -- a description which, when
interpreted in light of the commentary provided in the relevant
Explanatory Notes precludes classification of "varistors" of
heading 8533, HTSUS, from inclusion in heading 8541, HTSUS.
Accordingly, insofar as the subject merchandise is not defined in
Note 5 to Chapter 85, that Note does not apply to the same.
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HOLDING:
In view of the foregoing, GE-MOV varistors are properly
classifiable under subheading 8533.40.00, HTSUS, as "[e]lectrical
resistors . . . [o]ther variable resistors . . . ," dutiable at
the rate of 6 percent ad valorem.
Sincerely,
John Durant, Director
Commercial Rulings Division
Source: rulings.cbp.gov — ruling 084651, retrieved 2026-10-12T05:18:36Z, republished verbatim. This digest is informational; only CBP issues binding rulings.