-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Ey2ErLQH3ujG32GdKl0TWsXa6771SfSibFodw60DGW80IIy6bbSz1mciwYp7M4+n
 XCjknOqWlyRkhDxrpHUDfA==

<SEC-DOCUMENT>0000922423-05-000851.txt : 20050516
<SEC-HEADER>0000922423-05-000851.hdr.sgml : 20050516
<ACCEPTANCE-DATETIME>20050516163638
ACCESSION NUMBER:		0000922423-05-000851
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050516
FILED AS OF DATE:		20050516
DATE AS OF CHANGE:		20050516

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			OWYANG KING
		CENTRAL INDEX KEY:			0001257794

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-03698
		FILM NUMBER:		05835032

	BUSINESS ADDRESS:	
		STREET 1:		VISHAY SILICONIX
		STREET 2:		2201 LAURELWOOD RD.
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SILICONIX INC
		CENTRAL INDEX KEY:			0000090283
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				941527868
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2201 LAURELWOOD RD
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95056
		BUSINESS PHONE:		4089888000

	MAIL ADDRESS:	
		STREET 1:		2201 LAURELWOOD RD
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95056
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>kl00543_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-05-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000090283</issuerCik>
        <issuerName>SILICONIX INC</issuerName>
        <issuerTradingSymbol>SILI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001257794</rptOwnerCik>
            <rptOwnerName>OWYANG KING</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2201 LAURELWOOD ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SANTA CLARA,</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95054</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-05-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4261</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person sold 4,261 shares of the issuer in exchange for 13,102 shares (and cash representing a fractional share)
of Vishay Intertechnology, Inc., a Delaware Corporation, at an exchange ratio of 3.075 per share.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ King Owyang</signatureName>
        <signatureDate>2005-05-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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