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                                                                     EXHIBIT 5.1

                                CTS CORPORATION
                            905 West Boulevard North
                             Elkhart, Indiana 46514

                               November 10, 1999

CTS Corporation
905 West Boulevard North
Elkhart, Indiana 46514

       Re: Registration Statement on Form S-3 of up to
          $500,000,000 of Securities of CTS Corporation

Ladies and Gentlemen:

    I am General Counsel, Secretary and an Executive Vice President of the
Company and have acted as counsel to CTS Corporation, an Indiana corporation
(the "Company"), in connection with the authorization of the possible issuance
and sale from time to time by the Company of (i) certain debt securities of the
Company (the "Debt Securities"), (ii) shares of the Company's common stock,
without par value (the "Common Stock"), (iii) shares of one or more series of
the Company's preferred stock, without par value (the "Preferred Stock"), and
(iv) certain warrants to purchase Debt Securities, Common Stock, Preferred
Stock, or a combination thereof (the "Warrants"), in each case as contemplated
by the Company's Registration Statement on Form S-3 (the "Registration
Statement"). The Debt Securities, Common Stock, Preferred Stock, and Warrants
are collectively referred to herein as the "Securities." Except as otherwise
defined herein, capitalized terms that are defined in the Registration Statement
are used herein as so defined.

    I have examined such documents, records, and matters of law as I have deemed
necessary for purposes of this opinion, and based thereupon, I am of the opinion
that:

    1.  The Debt Securities, when (a) duly executed by the Company and
       authenticated by the Trustee in accordance with the provisions of the
       Indenture and issued and sold in accordance with the Registration
       Statement and (b) delivered to the purchaser or purchasers thereof upon
       receipt by the Company of such lawful consideration therefor as the
       Company's Board of Directors (or a duly authorized committee thereof or a
       duly authorized officer of the Company) may determine, will be valid and
       binding obligations of the Company.

    2.  The Common Stock, when (a) issued and sold in accordance with the
       Registration Statement and (b) delivered to the purchaser or purchasers
       thereof upon receipt by the Company of such lawful consideration therefor
       as the Company's Board of Directors (or a duly authorized committee
       thereof or a duly authorized officer of the Company) may determine,
       assuming that the Company at such time has authorized but unissued shares
       of Common Stock remaining under its Articles of Incorporation, will be
       validly issued, fully paid and nonassessable.

    3.  The Preferred Stock, when (a) issued and sold in accordance with the
       Registration Statement and the provisions of an applicable Certificate of
       Designation that has been duly adopted by the Board of Directors of the
       Company and duly filed in accordance with Indiana law and (b) delivered
       to the purchaser or purchasers thereof upon receipt by the Company of
       such lawful consideration therefor as the Company's Board of Directors
       (or a duly authorized committee thereof or a duly authorized officer of
       the Company) may determine, will be validly issued, fully paid and
       nonassessable.

    4.  The Warrants, when (a) issued and sold in accordance with the
       Registration Statement and the provisions of an applicable Warrant
       Agreement and (b) delivered to the purchaser or purchasers thereof upon
       receipt by the Company of such lawful consideration therefor as the
       Company's
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CTS Corporation
November 10, 1999
Page 2

       Board of Directors (or a duly authorized committee thereof or a duly
       authorized officer of the Company) may determine, will be valid and
       binding obligations of the Company.

    In rendering the foregoing opinions, I have assumed that (i) the definitive
terms of each class and series of the Securities not presently provided for in
the Indenture or the Company's Articles of Incorporation will have been
established in accordance with all applicable provisions of law, the Indenture,
the Company's Articles of Incorporation and Bylaws, and the authorizing
resolutions of the Company's Board of Directors, and reflected in appropriate
documentation approved by us and, if applicable, duly executed and delivered by
the Company and any other appropriate party, (ii) the interest rate on the Debt
Securities will not be higher than the maximum lawful rate permitted from time
to time under applicable law, (iii) any Securities consisting of Common Stock or
Preferred Stock, and any Common Stock or Preferred Stock for or into which any
other Securities are exercisable, exchangeable or convertible, will have been
duly authorized and reserved for issuance, (iv) each Warrant Agreement will have
been duly authorized, executed and delivered by, and will constitute a valid and
binding obligation of, each party thereto, (v) the Registration Statement, and
any amendments thereto, will have become effective, (vi) a Prospectus Supplement
describing each class or series of Securities offered pursuant to the
Registration Statement will have been filed with the Commission, (vii) the
resolutions authorizing the Company to register, offer, sell, and issue the
Securities will remain in effect and unchanged at all times during which the
Securities are offered, sold, or issued by the Company, and (viii) all
Securities will be issued in compliance with applicable federal and state
securities laws.

    In rendering the foregoing opinion, I have relied as to certain factual
matters upon certificates of officers of the Company, and we have not
independently checked or verified the accuracy of the statements contained
therein. In rendering the foregoing opinion, our examination of matters of law
has been limited to the laws of the State of Indiana and the federal laws of the
United States of America, as in effect on the date hereof.

    I hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement and to the reference to me in the Prospectus under the
caption "Validity of Securities." In giving such consent, I do not thereby admit
that I am within the category of persons whose consent is required under
Section 7 of the Securities Act or the rules and regulations promulgated
thereunder.

                                    Very truly yours,
                                    /s/ JEANNINE M. DAVIS
                                    EXECUTIVE VICE PRESIDENT ADMINISTRATION,
                                    GENERAL COUNSEL AND SECRETARY
