PROMISSORY NOTE

Borrower: ARIZONA INSTRUMENT CORPORATION      Lender:     Silicon Valley Bank
          4144 East Wood Street               Embarcadero/National Accounts
          Phoenix, AZ 85040                   1731 Embarcadero, Suite 220
                                                  Palo, CA 94303

Principal Amount: $1,250,000.00  
Initial Rate: 10.750% 
Date of Note: November 7, 1995

PROMISE TO PAY. ARIZONA INSTRUMENT  CORPORATION  ("Borrower") promises to pay to
Silicon Valley Bank  ("Lender"),  or order, in lawful money of the United States
of America,  the principal  amount of One Million Two Hundred  Fifty  Thousand &
00/100 Dollars  ($1,250,000.00),  together with Interest on the unpaid principal
balance from November 7, 1995, until paid In full.

PAYMENT.  Subject to any payment  changes  resulting  from changes In the Index,
Borrower will pay this loan in 41 principal  payments of $29,761.91 each and one
final  principal and Interest  payment of $30,028.31.  Borrowees first principal
payment is due December 7,1995, and all subsequent principal payments are due on
the same day of each month after that.  In addition,  Borrower  will pay regular
monthly  payments of all accrued  unpaid  Interest due as of each payment  date.
Borrowees  first  interest  payment is due December 7, 1995,  and all subsequent
Interest  payments are due on the same day of each month after that.  Borrower's
final payment due May 7, 1999,  will be for all  principal and accrued  Interest
not yet paid.  Interest on this Note is computed  on a 365/360  simple  interest
basis; that is, by applying the ratio of the annual interest rate over a year of
360 days,  multiplied by the outstanding  principal  balance,  multiplied by the
actual number of days the principal  balance is  outstanding.  Borrower will pay
Lender at  Lendees  address  shown  above or at such  other  place as Lender may
designate in writing.  Unless  otherwise  agreed or required by applicable  law,
payments will be applied first to accrued  unpaid  interest,  then to principal,
and any remaining amount to any unpaid collection costs and late charges.

VARIABLE INTEREST RATE. The interest rate on this Note is subject to change from
time to time  based on  changes  in an index  which is  Lenders  Prime Rate (the
"Index).  This is the rate Lender charges,  or would charge, on 90-day unsecured
loans to the most creditworthy corporate customers.  This rate may or may not be
the lowest  rate  available  from  Lender at any given  time.  Lender  will tell
Borrower the current Index rate upon  Borrowees  request.  Borrower  understands
that  Lender may make loans  based on other  rates as well.  The  interest  rate
change  will not occur more often than each time the prime rate is  adjusted  by
Silicon Valley Bank. The Index currently Is 8.750% per annum.  The Interest rate
to be applied to the unpaid principal  balance of this Note will be at a rate of
2.000 percentage points over the Index,  resulting In an Initial rate of 10.750%
per annum. NOTICE: Under no circumstances will the interest rate on this Note be
more than the maximum rate allowed by applicable law.

PREPAYMENT. Borrower agrees that all loan fees and other prepaid finance charges
are  earned  fully as of the date of the loan and will not be  subject to refund
upon early  payment  (whether  voluntary or as a result of  default),  except as
otherwise  required by law.  Except for the foregoing,  Borrower may pay without
penalty  all or a portion  of the  amount  owed  earlier  than it is due.  Early
payments will not,  unless agreed to by Lender in writing,  relieve  Borrower of
Borrowers  obligation to continue to make payments  under the payment  schedule.
Rather,  they will reduce the  principal  balance due and may result in Borrower
making fewer payments.

DEFAULT.  Borrower  will be in  default  if any of the  following  happens:  (a)
Borrower  fails to make any payment when due.  (b)  Borrower  breaks any promise
Borrower has made to Lender, or Borrower fails to comply with or to perform when
due any other term, obligation, covenant, or condition contained in this Note or
any agreement  related to this Note, or in any other  agreement or loan Borrower
has with Lender and has not been removed,  cured, discharged or rescinded within
ten (10)  days.  (c)  Borrower  defaults  under any loan,  extension  of credit,
security  agreement,  purchase or sales agreement,  or any other  agreement,  in
favor of any other  creditor  or person,  in an amount in excess of Two  Hundred
Thousand  Dollars  ($200,000.00),  that may  materially  affect any of Borrowers
property  or  Borrowees   ability  to  repay  this  Note  or  perform  Borrowees
obligations  under  this  Note  or  any  of  the  Related  Documents.   (d)  Any
representation  or  statement  made or  fumished  to  Lender by  Borrower  or on
Borrowers behalf is false or misleading in any material respect either now or at
the time made or  furnished.  (e) Borrower  becomes  insolvent or an  insolvency
proceeding is commenced  against  Borrower and is not dismissed or stayed within
thirty (30) days  (provided that no advances will be made prior to the dismissal
of such  insolvency  proceeding),  a  receiver  is  appointed  for  any  part of
Borrowers  property,  Borrower makes an assignment for the benefit of creditors,
or any proceeding is commenced  either by Borrower or against Borrower under any
bankruptcy or insolvency  laws.  (f) Any creditor tries to take any of Borrowers
property on or in which Lender has a lien or security interest.  This includes a
gamishment  of any of  Borrowees  accounts  with  Lender.  (g) Any of the events
described in this default  section  occurs with respect to any guarantor of this
Note. (h) A material adverse change occurs in Borrowees financial condition,  or
Lender  believes the prospect of payment or performance of the  Indebtedness  is
impaired.

LENDER'S  RIGHTS.  Upon default,  Lender may declare the entire unpaid principal
balance on this Note and all accrued unpaid interest  immediately  due,  without
notice,  and then Borrower will pay that amount.  Upon Borrowees  failure to pay
all amounts declared due pursuant to this section, including failure to pay upon
final maturity,  Lender, at its option,  may also, if permitted under applicable
law, do one or both of the following: (a) increase the variable interest rate on
this Note to 7.000  percentage  points  over the  Index,  and (b) add any unpaid
accrued  interest to principal and such sum will bear interest  therefrom  until
paid at the rate provided in this Note  (including any increased  rate).  Lender
may hire or pay someone else to help collect this Note if Borrower does not pay.
Borrower also will pay Lender that amount. This includes,  subject to any limits
under applicable law, Lendees attorneys' fees and Lenders legal expenses whether
or not there is a lawsuit,  including  attorneys'  fees and legal  expenses  for
bankruptcy proceedings (including efforts to modify or vacate any automatic stay
or injunction),  appeals, and any anticipated  postjudgment collection services.
Borrower  also will pay any court costs,  in addition to all other sums provided
by law.  This Note has been  delivered  to Lender and  accepted by Lender in the
State of California. If there Is a lawsuit Borrower agrees upon Lender's request
to submit to the jurisdiction of the courts of Santa Clara County,  the State of
California.  Lender and Borrower hereby waive the right to any jury trial in any
action, proceeding, or counterclaim brought by either Lender or Borrower against
the other.  (Initial  Here ) This Note shall be  governed  by and  construed  In
accordance with the laws of the State of California.

REQUEST TO DEBIT  ACCOUNTS.  Borrower will regularly  deposit all funds received
from its  business  activities  in  accounts  maintained  by Borrower at Silicon
Valley Bank.  Borrower  hereby  requests and  authorizes  Lender to debit any of
Borrowees accounts with Lender, specifically, without limitation, Account Number
for payments of principal and interest due on the loan and any other obligations
owing by Borrower to Lender.

Lender will notify  Borrower of all debits which Lender makes against  Borrowers
accounts.  Any such debts against Borrowees accounts in no way shall be deemed a
set-off.

LOAN AND  SECURITY  AGREEMENT.  This Note is subject to and shall be governed by
all the terms and  conditions  of the Amended  and  Restated  Loan and  Security
Agreement (Domestic Loan) dated March 15, 1995, between Lender and Borrower,  as
the same may be amended from time to time,  which  Amended and Restated Loan and
Security Agreement (Domestic Loan) is incorporated herein by this reference.

LOAN FEE.  This Note is subject to a loan fee in the amount of Ten  Thousand and
00/1 00 Dollars ($1 0,000.00) plus all out-of-pocket expenses.

ADDITIONAL PAYMENTS.  Notwithstanding  anything to the contrary contained in the
paragraph entitled "Payment", repayment of this Note shall be accelerated to the
extent Borrower  generates excess cash flow.  Excess cash flow is defined as the
residual  proceeds  from the  following  calculation:  Quarterly net income plus
depreciation  and  non  cash  charges;  less  capital  expenditures,   scheduled
principal  payments on all  indebtedness  and aggregate  increase in net working
capital.  This calculation will be performed quartely.  Such additional payments
shall be due 45 days  after  close  of each  fiscal  quarter  at a rate of fifty
percent  (50%) of the  excess  cash flow  calculation  ("Additional  Payments').
Additional  Payments  shall be credited to this Note as payment  schedule in the
inverse  order  of  maturity  (i.e.  to the  backened  of  this  Note  repayment
schedule).

GENERAL  PROVISIONS.  Lender may delay or forgo  enforcing  any of its rights or
remedies under this Note without losing them.  Borrower and any other person who
signs, guarantees or endorses this Note, to the extent allowed by law, waive any
applicable statute of limitations  presentment,  demand for payment, protest and
notice  of  dishonor.  Upon any  change in the terms of this  Note,  and  unless
otherwise  expressly stated in writing, no party who signs this Note, whether as
maker,  guarantor,  accommodation  maker or  endorser,  shall be  released  from
liability.  All such parties  agree that Lender may renew or extend  (repeatedly
and for any length of time) this loan,  or  release  any party or  guarantor  or
collateral; or impair, fail to realize upon or perfect Lendees security interest
in the collateral;  and take any other action deemed necessary by Lender without
the consent of or notice to anyone.  All such parties also agree that Lender may
modify this loan without the consent of or notice to anyone other than the party
with whom the modification is made.



PRIOR TO SIGNING THIS NOTE,  BORROWER HAS READ AND UNDERSTOOD ALL THE PROVISIONS
OF THIS NOTE,  INCLUDING THE VARIABLE INTEREST RATE PROVISIONS.  BORROWER AGREES
TO THE TERMS OF THE NOTE AND  ACKNOWLEDGES  RECEIPT OF A  COMPLETED  COPY OF THE
NOTE.

BORROWER:

ARIZONA INSTRUMENT CORPORATION


By:__________________________
Name:________________________
Title:_________________________