[GRAPHIC OMITTED]      Silicon Valley Bank


                           Amendment to Loan Agreement

Borrower:                  Advanced Photonix, Inc.
Address:                   1240 Avenida Acaso
                           Camarillo, California  93012

Dated as of:               July 16, 1998



         THIS AMENDMENT TO LOAN AGREEMENT is entered into between SILICON VALLEY
BANK ("Silicon") and the borrower named above (the "Borrower").

The Parties  agree to amend the Loan and Security  Agreement  between them dated
September  6,  1995,  as  amended  by that  Amendment  to Loan  Agreement  dated
September 6, 1996 and as amended by that Amendment to Loan Agreement dated as of
July 15, 1997 (and as otherwise amended from time to time, the "Loan Agreement")
as follows,  effective  as of the date hereof.  (Capitalized  terms used but not
defined  in this  Agreement,  shall  have  the  meanings  set  forth in the Loan
Agreement.)

     1.   Amended  Schedule.  The  Schedule to Loan and  Security  Agreement  is
          hereby amended in its entirety and replaced with the Amended  Schedule
          to Loan and Security Agreement attached hereto.

     2.   Fee. Borrower shall concurrently  herewith pay a fee to Silicon in the
          amount of $2,500,  which shall be in addition to all  interest and all
          other amounts payable hereunder, and which shall not be refundable.
        
     3.   Representations True. Borrower represents and warrants to Silicon that
          all representations and warranties set forth in the Loan Agreement, as
          amended hereby, are true and correct.

     4.   General Provisions.  This Extension Agreement, the Loan Agreement, any
          prior written  amendments to the Loan Agreement  signed by Silicon and
          the Borrower,  and the other written documents and agreements  between
          Silicon and the Borrower set forth in full all of the  representations
          and  agreements  of the parties  with  respect to the  subject  matter
          hereof  and   supersede   all  prior   discussions,   representations,
          agreements and understandings  between the parties with respect to the
          subject hereof.  Except as herein expressly amended,  all of the terms
          and  provisions of the Loan  Agreement,  as so amended,  and all other
          documents  and  agreements  between  Silicon  and the  Borrower  shall
          continue in full force and effect and the same are hereby ratified and
          confirmed.

   Borrower:                                           Silicon:

ADVANCED PHOTONIX, INC.                           SILICON VALLEY BANK


By   /s/Harry Melkonian                           By  Karl R. Brier
     ------------------                               -------------
    President or Vice President
                                                  Title  Vice President
                                                         --------------

By  /s/P. J. Holmes
    -------------------
    Secretary or Ass't Secretary
   


 [GRAPHIC OMITTED]      SILICON VALLEY BANK
                                   Schedule to

                           Loan and Security Agreement

Borrower:                  Advanced Photonix, Inc.
Address:                   1240 Avenida Acaso
                           Camarillo, California  93012

Dated:                     July 16, 1998

         THIS  SCHEDULE is an integral  part of the Loan and Security  Agreement
between  Silicon  Valley  Bank   ("Silicon")   and  the   above-named   borrower
("Borrower") of even date.

Credit Limit
     (Section 1.1): An amount not to exceed the lesser of: (i) $1,000,000 at any
          one time  outstanding;  or (ii) 75% * of the Net Amount of  Borrower's
          accounts,   which  Silicon  in  its  discretion   deems  eligible  for
          borrowing.  "Net  Amount" of an account  means the gross amount of the
          account,  minus all applicable  sales,  use,  excise and other similar
          taxes and minus all  discounts,  credits and  allowances of any nature
          granted or claimed.  
          * (provided that on and after a Borrowing Audit (as defined in Section
          4.5 of the Loan  Agreement),  this  percentage  may be modified in the
          reasonable  discretion  of  Silicon  based on the  results of any such
          audit)
          Without limiting the fact that the determination of which accounts are
          eligible  for  borrowing  is a matter  of  Silicon's  discretion,  the
          following  will  not  be  deemed  eligible  for  borrowing:   accounts
          outstanding  for more than 90 days  from the  invoice  date,  accounts
          subject to any contingencies, accounts owing from the United States or
          any department,  agency or instrumentality of the United States or any
          state,  city or  municipality,  accounts  owing from an account debtor
          outside  the United  States  (unless  pre-  approved by Silicon in its
          discretion,  or backed by a letter of credit  satisfactory to Silicon,
          or FCIA  insured  satisfactory  to Silicon),  accounts  owing from one
          account  debtor to the extent  they  exceed 25% of the total  eligible
          accounts  outstanding,  accounts  owing from an affiliate of Borrower,
          and accounts  owing from an account  debtor to whom Borrower is or may
          be liable for goods  purchased  from such account debtor or otherwise.
          In addition,  if more than 50% of the  accounts  owing from an account
          debtor are outstanding  more than 90 days from the invoice date or are
          otherwise  not eligible  accounts,  then all accounts  owing from that
          account debtor will be deemed ineligible for borrowing.

Letter of Credit Sublimit                            
          Silicon, in its reasonable  discretion,  will from time to time during
          the term of this Agreement  issue letters of credit for the account of
          the Borrower ("Letters of Credit"),  in an aggregate amount at any one
          time  outstanding  not to exceed  $100,000,  upon the  request  of the
          Borrower,  provided  that, on the date the Letters of Credit are to be
          issued,  Borrower  has  available to it Loans in an amount equal to or
          greater  than the face  amount of the  Letters of Credit to be issued.
          
                                       1


          Prior to the issuance of any Letters of Credit, Borrower shall execute
          and  deliver to Silicon  Applications  for  Letters of Credit and such
          other  documentation  as Silicon  shall specify (the "Letter of Credit
          Documentation").  Fees for the Letters of Credit  shall be as provided
          in the  Letter of Credit  Documentation.  Letters of Credit may have a
          maturity  date up to twelve  months beyond the Maturity Date in effect
          from time to time,  provided  that if on the Maturity  Date, or on any
          earlier  effective  date of  termination,  there  are any  outstanding
          letters of credit  issued by Silicon or issued by another  institution
          based upon an application,  guarantee,  indemnity or similar agreement
          on the part of Silicon,  then on such date  Borrower  shall provide to
          Silicon cash  collateral  in an amount equal to the face amount of all
          such  letters of credit  plus all  interest,  fees and costs due or to
          become due in connection  therewith,  to secure all of the Obligations
          relating  to said  letters  of  credit,  pursuant  to  Silicon's  then
          standard form cash pledge agreement.  
          The Credit  Limit set forth above and the Loans  available  under this
          Agreement  at any time shall be reduced by the face  amount of Letters
          of Credit from time to time outstanding.

Interest Rate (Section 1.2):  
          A rate equal to the  "Prime  Rate" in effect  from time to time,  plus
          0.50%  per  annum.  Interest  shall be  calculated  on the  basis of a
          360-day year for the actual number of days elapsed. "Prime Rate" means
          the rate  announced  from time to time by Silicon as its "prime rate;"
          it is a base rate upon which other rates charged by Silicon are based,
          and it is not  necessarily  the best rate  available  at Silicon.  The
          interest rate applicable to the Obligations  shall change on each date
          there is a change in the Prime Rate.

Loan Origination Fee
(Section 1.3):                          See Amendment to Loan Agreement.

Maturity Date
(Section 5.1):                          July 15, 1999

Prior Names of Borrower
(Section 3.2):                          Xsirius Photonix, Inc.

Trade Names of Borrower
(Section 3.2):                          None

Other Locations and Addresses
(Section 3.3):                          None

Material Adverse Litigation
(Section 3.10):                         None

Negative Covenants-Exceptions
(Section 4.6):                          
          Without   Silicon's  prior  written  consent,   Borrower  may  do  the
          following,  provided that,  after giving effect  thereto,  no Event of
          Default has occurred and no event has occurred  which,  with notice or
          passage of time or both,  would  constitute  an Event of Default,  and
          provided that the following are done in compliance with all applicable
          laws, rules and regulations: (i) repurchase shares of Borrower's stock
          pursuant to any employee stock purchase or benefit plan, provided that
          the total  amount  paid by  Borrower  for such  stock  does not exceed
          $100,000 in any fiscal year.
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Financial Covenants
(Section 4.1):                          
          Borrower shall comply with all of the following covenants.  Compliance
          shall be  determined  as of the end of each  fiscal  month,  except as
          otherwise specifically provided below:
     
Quick Asset Ratio:  
          Borrower   shall  maintain  a  ratio  of  "Quick  Assets"  to  current
          liabilities of not less than 2.00 to 1.
     
Tangible Net Worth:                
          Borrower  shall  maintain  a  tangible  net  worth  of not  less  than
          $3,000,000.
     
Definitions:                       
          "Current  assets," and "current  liabilities"  shall have the meanings
          ascribed to them in  accordance  with  generally  accepted  accounting
          principles.
          "Tangible  net  worth"  means the  excess of total  assets  over total
          liabilities,   determined  in  accordance   with  generally   accepted
          accounting  principles,  excluding  however all assets  which would be
          classified as intangible  assets under generally  accepted  accounting
          principles,  including without limitation goodwill, licenses, patents,
          trademarks,   trade  names,   copyrights,   capitalized  software  and
          organizational costs, licences and franchises.
          "Quick  Assets"  means cash on hand or on  deposit  in banks,  readily
          marketable securities issued by the United States,  readily marketable
          commercial  paper rated "A-1" by Standard & Poor's  Corporation  (or a
          similar  rating by a similar  rating  organization),  certificates  of
          deposit and  banker's  acceptances,  and accounts  receivable  (net of
          allowance for doubtful accounts).
     
Subordinated Debt:                
          "Liabilities"  for purposes of the foregoing  covenants do not include
          indebtedness  which is  subordinated  to the  indebtedness  to Silicon
          under a  subordination  agreement  in form  specified by Silicon or by
          language  in the  instrument  evidencing  the  indebtedness  which  is
          acceptable to Silicon.

Other Covenants
(Section 4.1):                          
          Borrower  shall  at  all  times  comply  with  all  of  the  following
          additional covenants:
          1.  Banking  Relationship.  Borrower  shall at all times  maintain its
          primary banking relationship with Silicon.
          
          2. Monthly  Borrowing Base Certificate and Listing.  When any Loans or
          Obligations relating thereto are outstanding, within 20 days after the
          end of each month,  Borrower  shall  provide  Silicon with a Borrowing
          Base  Certificate in such form as Silicon shall  specify,  and 
          an  aged  listing  of  Borrower's  accounts  receivable  and  accounts
          payable.  At all other  times,  within  20 days  after the end of each
          quarter,   Borrower  shall  provide  Silicon  with  a  Borrowing  Base
          Certificate in such form as Silicon shall specify, and an aged listing
          of   Borrower's   accounts   receivable   and   accounts   payable  
          
          3.  Indebtedness.  Without  limiting  any of the  foregoing  terms  or
          provisions of this  Agreement,  Borrower shall not in the future incur
          indebtedness  for  borrowed  money,  except  for (i)  indebtedness  to
          Silicon, and (ii) indebtedness incurred in the future for the purchase
          price of or lease of equipment in an  aggregate  amount not  exceeding
          $750,000 at any time outstanding.
          
                                       3

          4. Update. At such time that the Borrower requests Loans such that the
          Obligations  outstanding  hereunder  shall exceed  $200,000,  Borrower
          shall supply an update to Silicon of the intellectual property portion
          of the  representations  and  warranties  form Borrower has previously
          supplied  to  Silicon  in order  to  allow  Silicon  to  prepare  such
          supplemental  security  agreements and take such additional actions as
          Silicon deems  necessary or advisable in order to perfect its security
          interest in such items of Borrower's intellectual property not already
          subject to Silicon's perfected security interest.

Borrower:

ADVANCED PHOTONIX, INC.


By  /s/Harry Melkonian
President or Vice President

By  /s/P. J. Holmes
Secretary or Ass't Secretary

Silicon:

SILICON VALLEY BANK


By  /s/Karl R. Brier
Title  Vice President

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