EXECUTION VERSION


                                 NINTH AMENDMENT
                                       TO
                                CREDIT AGREEMENT


     This NINTH AMENDMENT TO CREDIT  AGREEMENT (this  "Amendment"),  dated as of
September 19, 1997, is entered into by and among:

         (1) BEI  Electronics,  Inc.,  a  Delaware  corporation,  BEI  Sensors &
     Systems Company,  Inc., a Delaware  corporation  ("BEI  Sensors"),  Defense
     Systems  Company,  Inc. a Delaware  corporation,  and BEI  Medical  Systems
     Company,  Inc.,  a  Delaware  corporation  (each a  "Prior  Borrower"  and,
     collectively, the "Prior Borrowers");

         (2) Each of the financial  institutions  listed on the signature  pages
     hereof (each a "Lender" and, collectively, the "Lenders");

         (3) CIBC Inc., as agent for the Lenders (the "Agent"); and

         (4)  Canadian  Imperial  Bank of Commerce,  as the existing  Designated
     Issuer (the "Existing Designated Issuer").


                                    RECITALS

     A. Reference is made to that certain Credit  Agreement  dated as of June 1,
1993,  as  amended  by the  First  Amendment  to  Credit  Agreement  dated as of
September 3, 1993,  as amended by the Second  Amendment to Credit  Agreement and
Limited  Waiver dated as of April 1, 1994, as amended by the Third  Amendment to
Credit  Agreement  dated as of  September  30,  1994,  as  amended by the Fourth
Amendment to Credit  Agreement dated as of June 1, 1995, as amended by the Fifth
Amendment to Credit  Agreement dated as of June 1, 1996, as amended by the Sixth
Amendment to Credit  Agreement  dated as of October 31, 1996,  as amended by the
Seventh  Amendment to Credit  Agreement  dated as of February  28, 1997,  and as
amended by the Eighth  Amendment to Credit  Agreement  dated as of July 31, 1997
(as so amended,  the "Credit  Agreement") by and among the Prior Borrowers,  the
Lenders,  the Agent and the Existing  Designated Issuer.  Capitalized terms used
herein without  definition  shall have the same meanings herein set forth in the
Credit Agreement.

     B. The Prior  Borrowers now have  requested the Lenders,  the Agent and the
Existing  Designated Issuer to amend the Credit Agreement in certain respects so
as to provide that as of the  effectiveness of this Amendment,  only BEI Sensors
shall be



<PAGE>


permitted to request  Borrowings  under the  Revolving  Commitment  and shall be
obligated thereunder.  The Lenders, the Agent and the Existing Designated Issuer
are  willing  to agree to such  amendments  upon the  terms and  subject  to the
conditions set forth in this Amendment.


                                    AGREEMENT

     NOW,  THEREFORE,  in consideration of the above recitals and for other good
and  valuable  consideration,  the  receipt  and  adequacy  of which are  hereby
acknowledged,  the Prior  Borrowers,  the Agent,  the Lenders  and the  Existing
Designated Issuer hereby agree as follows:

     1.  Definitions,  Interpretation.  All capitalized  terms defined above and
elsewhere in this Amendment shall be used herein as so defined. Unless otherwise
defined  herein,  all  other  capitalized  terms  used  herein  shall  have  the
respective meanings given to those terms in the Credit Agreement,  as amended by
this Amendment.

     2.  Credit  Agreement  Amendments.  Subject  to  the  satisfaction  of  the
conditions  set forth in  paragraph  3 below,  the  Credit  Agreement  is hereby
amended as follows:

         (a) The  introductory  paragraph  of the  Credit  Agreement  is  hereby
     amended to read in its entirety as follows:

               This Credit  Agreement  dated as of June 1, 1993 (as  amended) is
         entered  into among BEI  Sensors & Systems  Company,  Inc.,  a Delaware
         corporation (the "Borrower"),  the financial  institutions named on the
         signature   pages  hereof  (each  a  "Lender"  and   collectively   the
         "Lenders"),  CIBC Inc.,  as Agent for the Lenders  (the  "Agent"),  and
         Canadian Imperial Bank of Commerce.

         (b) The definition of "Borrower" and  "Borrowers"  set forth in Section
     1.1 of the Credit  Agreement  is hereby  amended to read in its entirety as
     follows:

               "Borrower":  As defined  in the  introductory  paragraph  of this
         Agreement.

         (c) The definition of "Borrower  Guarantor" set forth in Section 1.1 of
     the Credit Agreement is hereby deleted.

         (d) The  definition of "Maturity  Date" set forth in Section 1.1 of the
     Credit Agreement is hereby amended to read in its entirety as follows:

               "Maturity Date": October 31, 1997.

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<PAGE>


         (e) (i) Each  reference in the Credit  Agreement to "a Borrower",  "the
     Borrowers",  "the  Borrower  or  Borrowers",  "any  Borrower",  "any of the
     Borrowers",  "each Borrower", "such Borrower", "such Borrower or Borrowers,
     "each such Borrower", "each such Borrower or Borrowers" and "the applicable
     Borrower  or  Borrowers"  is hereby  changed  to "the  Borrower;  provided,
     however,  that  each  reference  to "any  Borrower"  in the  definition  of
     "Disclosure Letter",  "Employee Benefit Plan" and "Multi-Employer  Plan" is
     hereby  changed  to "BEI  and its  consolidated  Subsidiaries";  (ii)  each
     reference in the Credit  Agreement to "the Borrowers'" is hereby changed to
     "the Borrower's";  (iii) each reference in the Credit Agreement to "each of
     their  respective" is hereby  changed to "its";  and (iv) each reference in
     the Credit  Agreement  to "the  Borrowers  agree",  "the  Borrowers  hereby
     agree",  "the  Borrowers  desire",   "the  Borrowers  hereby  grant",  "the
     Borrowers warrant and represent", "the Borrowers each acknowledge" and each
     similar  reference  in  which  it is  suggested  that  there  are  multiple
     Borrowers is hereby  changed so that each such  reference  refers to only a
     single Borrower.

         (f) Each  reference in the Credit  Agreement to "for whose  account the
     Letter of Credit was issued" is hereby deleted.

         (g) Clause (b) of the  definition  of  "Interest  Period"  set forth in
     Section  1.1 of the  Credit  Agreement  is  hereby  amended  to read in its
     entirety as follows:

               (b) the Borrower  may not select an Interest  Period with respect
         to any portion of  principal of a  Eurodollar  Rate Loan which  extends
         beyond a date on which the  Borrower  is  required  to make a scheduled
         payment of that portion of principal; and

         (h) Article VIII of the Credit Agreement is hereby deleted and replaced
     with the word "RESERVED".

     3. Effective  Date.  The amendments  effected by paragraph 2 above shall be
effective as of September 19, 1997 (the "Effective Date"), subject to receipt by
the Agent on or prior to the date of this  Amendment  of each of the  following,
each in form and substance satisfactory to the Agent:

         (a) This Amendment,  duly executed by the Prior Borrowers, BEI Sensors,
     the Lenders, the Agent and the Designated Issuer;

         (b) New Notes,  duly  executed by BEI Sensors and made  payable to each
     Lender; and

         (c) Evidence  satisfactory  to the Agent that all  corporate  and other
     proceedings taken or to be taken in

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<PAGE>


     connection  with the  transactions  contemplated  hereby and all  documents
     incidental thereto not previously found acceptable by the Agent,  acting on
     behalf of the Lenders,  and its counsel shall be  satisfactory  in form and
     substance  to the Agent and such  counsel,  and the Agent and such  counsel
     shall have received all such  counterpart  originals or certified copies of
     such documents as the Agent may reasonably request.

     4.  Borrowers'  Representations  and  Warranties.  In order to  induce  the
Lenders, the Agent and the Designated Issuer to enter into this Amendment and to
amend the Credit Agreement in the manner provided herein, BEI Sensors represents
and  warrants  to the  Lenders,  the Agent and the  Designated  Issuer  that the
following  are true and correct on the date of this  Amendment  and that,  after
giving effect to the  amendments  set forth in paragraph 2 above,  the following
will be true and correct on the Effective Date:

         (a) The  representations and warranties of BEI Sensors set forth in the
     Credit Agreement are true and correct in all material respects;

         (b) No Event of Default or Potential  Event of Default has occurred and
     is continuing; and

         (c) The Credit Agreement is in full force and effect.

     5.  Effect  of this  Amendment.  On and  after  the  Effective  Date,  each
reference  in the  Credit  Agreement  and any  related  documents  to the Credit
Agreement shall mean the Credit  Agreement as amended by this Amendment.  Except
as specifically amended by this Amendment,  the Credit Agreement shall remain in
full force and effect and is hereby  ratified and affirmed.  Except as otherwise
expressly provided in this Amendment, the execution,  delivery and effectiveness
of this Amendment  shall not operate as a waiver of any right,  power, or remedy
of any Lender,  the Agent or the Designated  Issuer,  nor constitute a waiver of
any provision of the Credit Agreement or any related documents.

     6.  Expenses.  BEI  Sensors  shall pay on demand  all  reasonable  fees and
expenses,  including  reasonable  attorneys' fees and expenses,  incurred by the
Agent in connection with the negotiation, preparation, execution and delivery of
this Amendment and all related documents, instruments and agreements.

     7. Counterparts.  This Amendment may be executed in any number of identical
counterparts,  any set of which signed by all the parties hereto shall be deemed
to constitute a complete, executed original for all purposes.

     8.  Governing  Law.  This  Amendment  shall be governed by and construed in
accordance with the laws of the State of California.

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<PAGE>


     IN WITNESS  WHEREOF,  the parties  have caused  this  Amendment  to be duly
executed and delivered by their respective officers thereunto duly authorized as
of the date first written above.

PRIOR BORROWERS:                            BEI ELECTRONICS, INC.


                                            By: Robert R. Corr
                                               ---------------------------------

                                            Title: TREASURER
                                                  ------------------------------


                                            BEI SENSORS & SYSTEMS COMPANY, INC.


                                            By: Robert R. Corr
                                               ---------------------------------

                                            Title: TREASURER
                                                  ------------------------------


                                            DEFENSE SYSTEMS COMPANY, INC.


                                            By: Robert R. Corr
                                               ---------------------------------

                                            Title: TREASURER
                                                  ------------------------------


                                            BEI MEDICAL SYSTEMS COMPANY, INC.


                                            By: Robert R. Corr
                                               ---------------------------------

                                            Title: TREASURER
                                                  ------------------------------


NEW BORROWER:                               BEI SENSORS & SYSTEMS COMPANY, INC.


                                            By: Robert R. Corr
                                               ---------------------------------

                                            Title: TREASURER
                                                  ------------------------------

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<PAGE>


LENDERS AND AGENT:                          CIBC INC., Individually and as Agent


                                            By: Cyd A. Petre
                                               ---------------------------------

                                            Title: AUTHORIZED SIGNATORY
                                                  ------------------------------


                                            CANADIAN IMPERIAL BANK of COMMERCE, 
                                            as the Designated Issuer


                                            By: Cyd A. Petre
                                               ---------------------------------

                                            Title: AUTHORIZED SIGNATORY
                                                  ------------------------------


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