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HQ 084651

August 2, 1989

CLA-2 CO:R:C:G 084651 KK


TARIFF NO.: 8533.40.00, HTSUS

Peter Buck Feller
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.


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.


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."


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
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

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."

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.


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.


John Durant, Director

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