EXHIBIT 10.2


                                 PROMISSORY NOTE

     THIS  PROMISSORY  NOTE ("Note") is made as of this July 9, 2002 by National
Scientific Corporation,  a Texas Corporation with offices at 14455 N. Hayden Rd.
Ste 202, Scottsdale, AZ. 85260, ("Maker") and executed between the Maker and Lou
L. Ross ("Lender").

WITNESSETH

     WHEREAS,  pursuant  to this Note,  Lender has agreed to loan to Maker a sum
certain; and

     WHEREAS,  Maker has agreed to repay such sum  certain  with  interest  at a
fixed time in the future;

     NOW, THEREFORE, Maker hereby covenants and agrees as follows:

ARTICLE I:  TERMS AND CONDITIONS

SECTION  1.01 -  AMOUNT:  Subject  to the  terms  of  this  Note,  Maker  hereby
unconditionally  promises to pay, for value received, to the order of Lender the
principal  sum of thirty three  thousand  nine  hundred  fifty four and eighteen
cents ($33,954.18) .

SECTION  1.02 - ANNUAL  INTEREST  RATE:  Subject to the terms of this Note,  the
principle amount of this note shall be paid with interest thereon at the rate of
six percent  (6%) per year  (computed  on the basis of a 360-day  year of twelve
30-day months) compounded annually.

SECTION 1.03 - EFFECTIVE  DATE:  The Effective Date shall mean the date on which
the funds  subject to this Note are released to Maker,  or the date this Note is
executed, whichever is later.

SECTION 1.04 - TERM: The term of this note shall be for eighteen months from the
Effective Date, with the principle and interest being paid in full at the end of
the term.

SECTION 1.05 - REPAYMENT  SCHEDULE:  The principal and interest shall be paid in
lawful money of the United States at the address of the Lender denoted below, or
at  such  other  place  the  Lender  shall  designate  in  writing,  by  monthly
installments  in the amount of three thousand  twenty two dollars and twenty two
cents  ($3,022.22) each, due and payable on the first of each month beginning on
the first day of the  seventh  month from the date this note is  executed or the
date on which the funds subject to this Note are released to Maker, whichever is
later.

SECTION 1.06 - PREPAYMENT:  Maker hereby  reserves the right to prepay this Note
in whole or in part without any premium or penalty.  All payments beyond the due
and payable  installments shall be applied first to accrued interest and then to
principle.

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SECTION 1.07 - DEFAULT:  If the  undersigned  Maker of this Note defaults in its
obligations  as set forth  above,  the Lender must give  written  notice of such
default  to the  Maker at the  below  address.  Upon  receiving  such  notice of
default,  if not cured by Maker within 10 calendar days, the entire note becomes
immediately due and payable.

ARTICLE II:  MISCELLANEOUS

SECTION 2.01 - ARBITRATION: Any controversy,  claim, or breach arising out of or
relating  to this  Note,  at the  discretion  of  Maker,  shall  be  settled  by
arbitration in accordance  with the  Arbitration  Rules of American  Arbitration
Association  in  Phoenix,  Arizona.  Judgment  upon the  award  rendered  by the
arbitrators may be entered in any court having jurisdiction  thereof. Each party
shall have the right of  discovery  as set forth in the  Federal  Rules of Civil
Procedure.

SECTION 2.02 - GOVERNING  LAW: This Note is governed by the laws of the State of
Arizona and venue shall be in County of Maricopa.

SECTION 2.03 - JURISDICTION:  Lender hereby submits to personal  jurisdiction in
the State of Arizona.

SECTION 2.04 - NOT USED.

SECTION  2.05 - NOTICE:  All  notices  shall be in  writing  and shall be deemed
delivered in person when delivered by courier,  overnight  delivery service,  or
mailed  postage  prepaid  by  Certified  or  Registered  Mail -- Return  Receipt
Requested -- to the person and address designated in this Note.

SECTION 2.06 - NOT USED.

SECTION 2.07 - NOT USED.

SECTION 2.08 - SEVERABILITY:  If any provision of this Note is rendered invalid,
the remaining provisions shall remain in full force and effect.

SECTION 2.09 - ASSURANCES:  Each party hereby  represents  and warrants that all
representations,  warranties,  recitals,  statements and information provided to
each other under this Note are true,  correct,  and  accurate to the best of its
knowledge.

     IN WITNESS  WHEREOF,  the Maker has  executed  this Note as of this 8th day
July, 2002.


MAKER National Scientific Corporation

ADDRESS:
14455 N. Hayden Rd. Ste 202
Scottsdale, AZ.  85260

/s/ Sam H. Carr
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Signature/Title of Corporate Officer,      CFO
                                      ---------------


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<PAGE>

LENDER:  L. L. "Lou" Ross

ADDRESS:

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/s/ Lou L. Ross
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Signature/Title of Lou L. Ross


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