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                         PATRIOT SCIENTIFIC CORPORATION


                                   EXHIBIT 4.3

               Form of 6% Convertible Subordinated Promissory Note
                  due September 30, 1998 aggregating $1,500,000
             (Individual Notes differ as to date, amount and Payee)
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                                                                     EXHIBIT 4.3

         THIS INSTRUMENT HAS NOT BEEN AND WILL NOT BE REGISTERED UNDER THE
         SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), IN RELIANCE UPON
         REGULATION S THEREUNDER, AND CANNOT BE OFFERED OR SOLD IN THE UNITED
         STATES OR TO, OR FOR THE ACCOUNT OR BENEFIT OF, ANY U.S. PERSON, EXCEPT
         PURSUANT TO REGULATION S OR ANOTHER AVAILABLE EXEMPTION FROM THE
         REGISTRATION REQUIREMENTS OF THE ACT.

                          (ALL AMOUNTS IN U.S. DOLLARS)

                         PATRIOT SCIENTIFIC CORPORATION

                   6% CONVERTIBLE SUBORDINATED PROMISSORY NOTE

                             Due September 30, 1998

      October ___, 1996                                  US$_________. 00
      Poway, California

         FOR VALUE RECEIVED, Patriot Scientific Corporation, the undersigned
      Delaware corporation (together with all successors, "Borrower"), hereby
      promises to pay to the order of

         Payee:
                           or his, her or its successors or assigns
                           (collectively, "Noteholder") at

         Address:

      or at such other address or addresses as Noteholder may subsequently
      designate in writing to Borrower, the full and true sum of____________ and
      NO/100 Dollars ($______________.00), due and payable in one (1)
      installment on or before September 30, 1998, unless sooner accelerated
      ("Maturity Date"), plus simple interest thereon at the rate of six percent
      (6.00%) per annum, in lawful monies of the United States of America.
      Interest shall accrue and be payable at the Maturity Date. If the Maturity
      Date should fall on a weekend or national holiday, payment shall be due on
      the following business day.

         1. Any payment shall be deemed timely made if received by Noteholder
      within ten (10) calendar days of the due date. Payments received shall be
      imputed first to late or penalty charges then due, next to interest
      payments then due, and next to the remaining principal balance.

         2. Borrower may not prepay the principal or any accrued interest amount
      due under this Note in full or in part without the prior written agreement
      of Noteholder.

         3. (a) The outstanding principal amount of this Note (or increments
      thereof of at least $50,000) and any proportionate accrued interest may,
      at any time and from time to time, be converted at the option of the
      Noteholder into fully paid, nonassessable shares of Common Stock of the
      Borrower, $.00001 par value per share, at the Conversion Price per share
      as hereinafter defined, subject to restrictions and limitations set forth
      herein. The Conversion Price shall be the lesser of (i) 80% of the average
      of the highest and lowest sale prices each day for the five trading days
      immediately preceding the date of conversion, but in no event shall the
      Conversion Price be less than $0.80 per share, or (ii) $2.00 per share. If
      there are no trades on any particular date, such date shall not count as
      one of the five trading days. The Common Stock of the Borrower into which
      principal is converted ("conversion shares") will not be registered under
      the Securities Act of 1933, as amended ("Act"), but shall be sold, issued
      and delivered in reliance upon Rule 903 of Regulation S under the Act.

                  (b) Certificates which are issued evidencing the conversion
      shares shall, unless and until removed in accordance with applicable law,
      bear an appropriate restrictive legend to the effect that the shares have
      not been 


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      registered under the Act but have been offered and sold in reliance upon
      Regulation S and may not, during the applicable restricted period, be
      offered or sold within the United States of America or to any "U.S.
      Person" (as defined in Rule 902 of Regulation S).

                  (c) Conversion shall be effected by Noteholder's writing which
      unequivocally expresses Noteholder's intent to effect the conversion and
      states the amount of principal being converted (the Company shall compute
      the proportionate accrued interest being converted) and tender of such
      writing and this original Note to Borrower. Conversion shall be deemed to
      occur on the date such writing is presented to Borrower by fax or other
      means as long as the original Note is received promptly thereafter. Upon
      such conversion duly made, Borrower shall execute a new Note of like tenor
      for the balance of the principal amount of this Note not converted to
      common stock, and deliver such new Note and common stock to Noteholder.
      Borrower shall bear all expenses and charges of issuing and delivering the
      conversion shares.

                  (d) The conversion rate set forth in paragraph 3(a) will be
      subject to adjustment if the Borrower is reorganized, merged, consolidated
      or party to a plan of exchange with another corporation pursuant to which
      shareholders of the Borrower receive any shares of stock or other
      securities, or in the event of any sale or other transfer of all or
      substantially all of the Borrower's assets, or in case of any
      reclassification of Borrower's common stock. Noteholder shall be entitled,
      after the occurrence of any such event, to receive on conversion thereof
      the kind and amount of shares of stock or other securities, cash or other
      property receivable upon such event by a holder of the number of Common
      Shares into which the principal balance of this Note at such time might
      have been converted immediately prior to occurrence of the event. In
      addition, the conversion rate set forth in paragraph 3(a) of this Note
      will be appropriately adjusted if the Borrower's common stock is split or
      combined.

         4. Forced Conversion. The Company is entitled, at its option, at any
      time when the trading price (being the average of the highest and lowest
      sale price of the Company's common stock on a particular date) of the
      Company's common stock has equaled or exceeded US$3.75 per share for ten
      consecutive trading days during which market sales occurred, upon five (5)
      days' prior written notice ("Notice of Mandatory Conversion") to the
      holders of the Notes, to require the holders of the Notes to convert the
      amount of principal outstanding and all interest accrued under the Notes
      through the date of the Notice of Mandatory Conversion into fully paid and
      nonassessable shares of Common Stock at a conversion price of US$2.00 per
      share of Common Stock. The Company shall notify the holder of the
      Company's intent to force conversion by giving written notice to the
      holder by facsimile or other electronic means, if possible, with original
      notice to follow by two-day courier. Conversion pursuant to this Section 4
      shall be effective with respect to each holder on the fifth (5th) day (the
      "Mandatory Conversion Effective Date") following the confirmed receipt by
      the holder or any other person at the holder's designated address of the
      original notice referred to in the preceding sentence.

                  Upon the effective date of forced conversion of a Note, the
      Note shall be deemed void and no longer shall constitute an obligation of
      the Company or evidence of an obligation, irrespective of when surrendered
      to the Company. This provision requires the Company to convert all
      principal and interest owing under all Notes outstanding at the time of
      forced conversion. The holder of a Note so converted shall be required to
      surrender the original of the forcibly converted Note as promptly as
      possible to the Company, which shall mark the Note "canceled" upon receipt
      and retain permanent custody of it. Upon the Company's receipt of the
      original Note, the Company shall deliver to the surrendering holder the
      shares of Common Stock called for by this provision.

         5. In the event that this Note is placed with an attorney for
      collection or that Noteholder resorts to legal process in order to enforce
      any rights under this Note, Borrower shall pay all reasonable costs,
      including attorneys' fees, thereby incurred by the Noteholder.

         IN WITNESS WHEREOF, the undersigned Borrower has executed this
      Promissory Note and has affixed hereto its corporate seal.

                                    PATRIOT SCIENTIFIC CORPORATION

                                    By /s/ ROBERT PUTNAM
                                       ----------------------
                                       AUTHORIZED OFFICER


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