<PAGE>
                                                                    Exhibit 4.15


              CERTIFICATE TO SET FORTH DESIGNATIONS, VOTING POWERS,
              PREFERENCES, LIMITATIONS, RESTRICTIONS, AND RELATIVE
                         RIGHTS OF SERIES G CONVERTIBLE
                    PREFERRED STOCK, $.01 PAR VALUE PER SHARE


      It is hereby certified that:

      I.    The name of the corporation is JMAR Technologies, Inc. (the
"CORPORATION"), a Delaware corporation.

      II. The certificate of incorporation of the Corporation, as amended,
authorizes the issuance of 5,000,000 shares of Preferred Stock, $.01 par value
per share, and expressly vests in the Board of Directors of the Corporation the
authority provided therein to issue all of said shares in one or more Series by
resolution or resolutions, to establish the designation and number and to fix
the relative rights and preferences of each series to be issued.

      III. The Board of Directors of the Corporation, pursuant to the authority
expressly vested in it, has adopted the following resolution creating a class of
Series G Preferred Stock:

      RESOLVED, that a portion of the authorized shares of Preferred Stock of
the Corporation shall be designated as a separate series possessing the rights
and preferences set forth below:

      1. Designation: Number of Shares. The designation of said series of
Preferred Stock shall be Series G Cumulative Convertible Preferred Stock (the
"SERIES G PREFERRED STOCK"). The number of shares of Series G Preferred Stock
shall be 200,000. Each share of Series G Preferred Stock shall have a stated
value equal to $10 (as adjusted for any stock dividends, combinations or splits
with respect to such shares) (the "STATED VALUE"), and $.01 par value.

      2. Ranking. The Series G Preferred Stock shall rank (i) prior to the
Corporation's common stock, par value $.01 per share ("COMMON STOCK"); (ii)
prior to any class or series of capital stock of the Corporation hereafter
created (unless such class or series of capital stock specifically, by its
terms, ranks senior to or Pari Passu with the Series G Preferred Stock); (iii)
on a parity with any class or series of capital stock of the Corporation
hereafter created specifically ranking, by its terms, on parity with the Series
G Preferred Stock ("PARI PASSU SECURITIES"); and (iv) junior to any class or
series of capital stock of the Corporation hereafter created specifically
ranking, by its terms, senior to the Series G Preferred Stock ("SENIOR
SECURITIES"), in each case as to distribution of assets upon liquidation,
dissolution or winding up of the Corporation, whether voluntary or involuntary.

      3.    Dividends.

            (a) Subject to Section 3(d), the Holders of outstanding shares of
Series G Preferred Stock shall be entitled to receive preferential dividends in
cash out of any funds of the Corporation legally available at the time for
declaration of dividends before any dividend or other distribution will be paid
or declared and set apart for payment on any shares of any Common Stock, or
other class of stock presently authorized or to be authorized, other than the
Corporation's Series A, Series B, Series C, Series D, Series E, Series F and
Series H Preferred Stock which shall be Senior Securities (the Common Stock, and
such other stock being hereinafter collectively the "JUNIOR STOCK") at the rate
of 2% simple interest per annum on the Stated Value per share of Series G
Preferred Stock (the "DIVIDEND RATE") then outstanding (as adjusted pursuant to
Section 3(d) below)


                                       1
<PAGE>
payable monthly commencing April 1, 2004 and on the first business day of each
consecutive calendar month thereafter (each a "Monthly Dividend Payment");
provided, however, that dividend payments may be made in fully paid and non
assessable registered shares of the Corporation's Common Stock at the Conversion
Price (as defined herein) then in effect, and the issuance of such additional
shares shall constitute full payment of such dividend.

            (b) The dividends on the Series G Preferred Stock at the rates
provided above shall be cumulative whether or not earned so that, if at any time
full cumulative dividends at the rate aforesaid on all shares of the Series G
Preferred Stock then outstanding from the date from and after which dividends
thereon are cumulative to the end of the monthly dividend period next preceding
such time shall not have been paid or declared and set apart for payment, or if
the full dividend on all such outstanding Series G Preferred Stock for the then
current dividend period shall not have been paid or declared and set apart for
payment, the amount of the deficiency shall be paid or declared and set apart
for payment (but without interest thereon) before any sum shall be set apart for
or applied by the Corporation or a subsidiary of the Corporation to the
purchase, redemption or other acquisition of the Series G Preferred Stock or
Parri Passu Securities and before any dividend or other distribution shall be
paid or declared and set apart for payment on any Junior Stock and before any
sum shall be set aside for or applied to the purchase, redemption or other
acquisition of Junior Stock.

            (c) Dividends on all shares of the Series G Preferred Stock shall
begin to accrue and be cumulative from and after the date of issuance thereof. A
dividend period shall be deemed to commence on the day following a Monthly
Dividend Payment date herein specified and to end on the next succeeding Monthly
Dividend Payment date herein specified.

            (d) If a current registration statement covering the Securities
shall have been declared effective by the Securities Exchange Commission, the
Dividend Rate shall be decreased by one-hundred basis points (100 b.p.) for each
incremental increase of twenty five percent (25%) of the volume weighted average
price of the Common Stock for the five (5) trading days prior to the first
calendar day of the month, above the Conversion Price (defined below) then in
effect. Commencing with the September 1, 2004 Monthly Dividend Payment and each
Monthly Dividend Payment thereafter, if the volume weighted average price of the
Common Stock for the five (5) days prior to the Monthly Dividend Payment is less
than the Conversion Price, the Dividend Rate for the next succeeding month shall
equal to the "prime rate" published in the Wall Street Journal from time to
time. If, after September 1, 2004, the volume weighted average price of the
common stock for the five (5) days prior to the Monthly Dividend Payment is
greater than the Conversion Price, then the Dividend Rate for such Monthly
Dividend Payment shall be equal to the "prime rate" minus 2% decreased by the
provisions of the first sentence of this Section 3(d).

      4.    Liquidation Rights.

            (a) Upon the dissolution, liquidation or winding-up of the
Corporation, whether voluntary or involuntary, the Holders of the Series G
Preferred Stock shall be entitled to receive before any payment or distribution
shall be made on the Junior Stock, out of the assets of the Corporation
available for distribution to stockholders, the Stated Value per share of Series
G Preferred Stock then outstanding and all accrued and unpaid dividends to and
including the date of payment thereof. Upon the payment in full of all amounts
due to Holders of the Series G Preferred Stock, the holders of the Common Stock
of the Corporation and any other class of Junior Stock shall receive all
remaining assets of the Corporation legally available for distribution. If the
assets of the Corporation available for distribution to the holders of the
Series G Preferred Stock shall be insufficient to permit payment in full of the
amounts payable as aforesaid to the holders of Series G Preferred Stock upon
such liquidation, dissolution or winding-up, whether voluntary or involuntary,
then all such assets of the Corporation shall be distributed ratably among the
holders of the Series G Preferred Stock.


                                       2
<PAGE>
            (b) Neither the purchase nor the redemption by the Corporation of
shares of any class of stock nor the merger or consolidation of the Corporation
with or into any other corporation or corporations nor the sale or transfer by
the Corporation of all or any part of its assets shall be deemed to be a
liquidation, dissolution or winding-up of the Corporation for the purposes of
this Section 4.

      5. Conversion into Common Stock. Shares of Series G Preferred Stock shall
have the following conversion rights and obligations:

            (a) Subject to the further provisions of this Section 5, each holder
of shares of Series G Preferred Stock shall have the right at any time
commencing after the issuance of the Series G Preferred Stock to such holder to
convert such shares into fully paid and non-assessable shares of Common Stock of
the Corporation (as further subject to the limitation set forth in Section 5(i)
below) at the Conversion Price provided in Section 5(b) below. All issued or
accrued but unpaid dividends may be converted at the election of the holder
simultaneously with the conversion of the Series G Preferred Stock being
converted.

      Notwithstanding anything contained herein to the contrary, no holder of
Series G Preferred Stock shall be entitled to convert pursuant to the terms of
this Section 5(a) that amount of the Preferred Stock convertible into that
number of shares of Common Stock which would result in the Holder's beneficial
ownership (as defined below) of the Corporation's Common Stock being in excess
of 4.99% of the outstanding shares of Common Stock of the Company. For the
purposes of the immediately preceding sentence, beneficial ownership shall be
determined in accordance with Section 13(d) of the Exchange Act and Regulation
13d-3 thereunder. Subject to the foregoing, a holder of Series G Preferred Stock
shall not be limited to aggregate conversions of only 4.99%. A holder of Series
G Preferred Stock may void the conversion limitation described in this Section
5(a) upon 75 days prior notice to the Corporation or upon an Event of Default
hereunder.

            (b) The number of shares of Common Stock issuable upon conversion of
each share of Series G Preferred Stock shall equal (i) the sum of (A) the Stated
Value per share, as amended pursuant to Section 5 hereof, and (B) at the
holder's election, accrued and unpaid dividends on such share, divided by (ii)
$3.28 (the "CONVERSION PRICE").

            If after the Default Notice Period (as defined below) the
Corporation has not repaid in full the amounts then due hereunder or cured the
Event of Default, then the Conversion Price shall be reduced and shall be equal
to the lower of (i) the Conversion Price; or (ii) eighty percent (80%) of the
average of the three (3) lowest closing prices for the Common Stock on whichever
Principal Market is at the time the principal trading exchange or market for the
Common Stock, or on any securities exchange or other securities market on which
the Common Stock is then being listed or traded, for the thirty (30) trading
days prior to but not including the Conversion Date.

            (c) The holder of any certificate for shares of Series G Preferred
Stock desiring to convert any of such shares may give notice of its decision to
convert the shares into common stock by delivering, along with the
certificate(s) representing the shares of Series G Preferred Stock to be
converted if requested by the Corporation, an executed and completed notice of
conversion ("NOTICE OF CONVERSION") to the Corporation (the "CONVERSION DATE").
Each date on which a notice of conversion is delivered or telecopied to the
Corporation in accordance with the provisions hereof shall be deemed a
Conversion Date. A form of Notice of Conversion that may be employed by a holder
is annexed hereto as Exhibit A. The Corporation will cause the transfer agent to
transmit the certificates representing the shares of the Corporation's Common
Stock issuable


                                       3
<PAGE>
upon conversion of the Series G Preferred Stock (and a certificate representing
the balance of the Preferred Stock not so converted, if requested by Purchaser)
to the holder by (i) to the extent permitted by the transfer agent for the
Common Stock, crediting the account of the Holder's prime broker with the
Depository Trust Corporation ("DTC") through its Deposit Withdrawal Agent
Commission ("DWAC") system, or (ii) otherwise, by delivery to the Holder of a
stock certificate representing such shares of Common Stock, within three (3)
business days after receipt by the Corporation of the Notice of Conversion and
the certificate(s) representing the shares of Series G Preferred Stock to be
converted (the "DELIVERY DATE"). The Corporation is obligated to deliver to the
holder simultaneously with the aforedescribed Common Stock, at the election of
the Holder, additional Common Stock representing the conversion at the
Conversion Price, of dividends accrued on the Series G Preferred Stock being
converted.

            The Corporation understands that a delay in the delivery of the
Common Stock in the form required pursuant to this Section beyond the Delivery
Date could result in economic loss to the Holder. In the event that the
Corporation fails to direct its transfer agent to deliver the Common Stock to
the Holder within the time frame set forth in Section 5 and the Common Stock is
not delivered to the Holder by the Delivery Date, as compensation to the Holder
for such loss, the Corporation agrees to pay late payments to the Holder for
late issuance of the Common Stock in the form required pursuant to this Section
5 in the amount equal to $500 per business day after the Delivery Date. The
Corporation shall pay any payments incurred under this Section in immediately
available funds upon demand and, in the case of actual damages, accompanied by
reasonable documentation of the amount of such damages.

            In the case of the exercise of the conversion rights set forth in
Section 5(a) the conversion privilege shall be deemed to have been exercised and
the shares of Common Stock issuable upon such conversion shall be deemed to have
been issued upon the date of receipt by the Corporation of the Notice of
Conversion. The person or entity entitled to receive Common Stock issuable upon
such conversion shall, on the date such conversion privilege is deemed to have
been exercised and thereafter, be treated for all purposes as the record holder
of such Common Stock and shall on the same date cease to be treated for any
purpose as the record holder of such shares of Series G Preferred Stock so
converted.

            Upon the conversion of any shares of Series G Preferred Stock no
adjustment or payment shall be made with respect to such converted shares on
account of any dividend on the Common Stock, except that the holder of such
converted shares shall be entitled to be paid any dividends declared on shares
of Common Stock after conversion thereof.

            The Corporation shall not be required, in connection with any
conversion of Series G Preferred Stock, and payment of dividends on Series G
Preferred Stock to issue a fraction of a share of its Series G Preferred Stock
and shall instead deliver a stock certificate representing the next whole
number.

            In the event of any conversions of shares of Series G Preferred
Stock in part pursuant to this Section 5, such conversions shall be deemed to
constitute conversions of outstanding redemption amount applying to Monthly
Amounts (as defined in Section 10 below) for the Repayment Dates (as defined in
Section 10 below) in chronological order. By way of example, if the original
stated amount of the Series G Preferred Stock is $2,000,000 and the Holder
converted $ 50,000 of such original stated amount prior to the first Repayment
Date, then (1) the principal amount of the Monthly Amount due on the first
Repayment Date would equal $0, (2) the principal amount of the Monthly Amount
due on the second Repayment Date would equal $25,000 and (3) the principal
amount of the Monthly Amount due on each of the remaining Repayment Dates would
be $37,500.


                                       4
<PAGE>
            (d) The Conversion Price determined pursuant to Section 5(b) shall
be subject to adjustment from time to time as follows:

                  (i) In case the Corporation shall at any time (A) declare any
dividend or distribution on its Common Stock or other securities of the
Corporation other than the Series A, B, C, D, E, F or H Preferred Stock, (B)
split or subdivide the outstanding Common Stock, (C) combine the outstanding
Common Stock into a smaller number of shares, or (D) issue by reclassification
of its Common Stock any shares or other securities of the Corporation, then in
each such event the Conversion Price shall be adjusted proportionately so that
the holders of Series G Preferred Stock shall be entitled to receive the kind
and number of shares or other securities of the Corporation which such holders
would have owned or have been entitled to receive after the happening of any of
the events described above had such shares of Series G Preferred Stock been
converted immediately prior to the happening of such event (or any record date
with respect thereto). Such adjustment shall be made whenever any of the events
listed above shall occur. An adjustment made to the Conversion Price pursuant to
this Section 5(d)(i) shall become effective immediately after the effective date
of the event for the event.

            (e) (i) In case of any merger of the Corporation with or into any
other corporation (other than a merger in which the Corporation is the surviving
or continuing corporation and which does not result in any reclassification,
conversion, or change of the outstanding shares of Common Stock) then unless the
right to convert shares of Series G Preferred Stock shall have terminated, as
part of such merger lawful provision shall be made so that holders of Series G
Preferred Stock shall thereafter have the right to convert each share of Series
G Preferred Stock into the kind and amount of shares of stock and/or other
securities or property receivable upon such merger by a holder of the number of
shares of Common Stock into which such shares of Series G Preferred Stock might
have been convertible by the holder immediately prior to such consolidation or
merger. Such provision shall also provide for adjustments that shall be as
nearly equivalent as may be practicable to the adjustments provided for in
Section (d) of this Section 5. The foregoing provisions of this Section 5(e)
shall similarly apply to successive mergers.

                  (ii) In case of any sale or conveyance to another person or
entity of the property of the Corporation as an entirety, or substantially as an
entirety, in connection with which shares or other securities or cash or other
property shall be issuable, distributable, payable, or deliverable for
outstanding shares of Common Stock, then, unless the right to convert such
shares shall have terminated, lawful provision shall be made so that the holders
of Series G Preferred Stock shall thereafter have the right to convert each
share of the Series G Preferred Stock into the kind and amount of shares of
stock or other securities or property that shall be issuable, distributable,
payable, or deliverable upon such sale or conveyance with respect to each share
of Common Stock immediately prior to such conveyance.

            (f) Whenever the number of shares to be issued upon conversion of
the Series G Preferred Stock is required to be adjusted as provided in this
Section 5, the Corporation shall forthwith compute the adjusted number of shares
to be so issued and prepare a certificate setting forth such adjusted conversion
amount and the facts upon which such adjustment is based; and the Corporation
shall mail to each holder of record of Series G Preferred Stock notice of such
adjusted conversion price.

            (g)   In case at any time the Corporation shall propose:

                  (i) to pay any dividend or distribution payable in shares upon
its Common Stock

                                       5
<PAGE>
or make any distribution (other than cash dividends) to the holders of its
Common Stock; or

                  (ii)  to offer for subscription to the holders of its
Common Stock any additional shares of any class or any other rights; or

                  (iii) any capital reorganization or reclassification of its
shares or the merger of the Corporation with another corporation (other than a
merger in which the Corporation is the surviving or continuing corporation and
which does not result in any reclassification, conversion, or change of the
outstanding shares of Common Stock); or

                  (iv) the voluntary dissolution, liquidation or winding-up of
the Corporation;

then, and in any one or more of said cases, the Corporation shall cause at least
fifteen (15) days prior notice of the date on which (A) the books of the
Corporation shall close or a record be taken for such stock dividend,
distribution, or subscription rights, or (B) such capital reorganization,
reclassification, merger, dissolution, liquidation or winding-up shall take
place, as the case may be, to be mailed to the Transfer Agent for the Series G
Preferred Stock and to the holders of record of the Series G Preferred Stock.

            (h) So long as any shares of Series G Preferred Stock shall remain
outstanding and the holders thereof shall have the right to convert the same in
accordance with provisions of this Section 5 the Corporation shall at all times
reserve from the authorized and unissued shares of its Common Stock a sufficient
number of shares to provide for such conversions.

            (i) Overall Limit on Common Stock Issuable. The number of shares of
Common Stock issuable by the Corporation and acquirable by the Holder under all
securities issued by the Company to the Holder, shall not exceed an aggregate of
4,769,535 shares, subject to appropriate adjustment for stock splits, stock
dividends, or other similar recapitalizations affecting the Common Stock (the
"MAXIMUM COMMON STOCK ISSUANCE"), unless the issuance of shares hereunder in
excess of the Maximum Common Stock Issuance shall first be approved by the
Corporation's shareholders provided, however, that any shares of Common Stock
issued to Holder upon conversion of convertible securities or upon exercise of
warrants and subsequently sold by the Holder shall be excluded from the
calculation of the aggregate Maximum Common Stock Issuance. If at any point in
time and from time to time the number of shares of Common Stock issued pursuant
to conversion of the Preferred Stock, together with the number of shares of
Common Stock that would then be issuable by the Corporation in the event of the
conversion or exercise of all other securities issued by the Company, would
exceed the Maximum Common Stock Issuance but for this Section, the Corporation
shall promptly call a shareholders meeting to obtain shareholder approval for
the issuance of the shares of Common Stock hereunder in excess of the Maximum
Common Stock Issuance if required by the NASDAQ SmallCap listing requirements.

            (j) The Corporation shall pay the amount of any and all issue taxes
(but not income taxes) which may be imposed in respect of any issue or delivery
of stock upon the conversion of any shares of Series G Preferred Stock, but all
transfer taxes and income taxes that may be payable in respect of any change of
ownership of Series G Preferred Stock or any rights represented thereby or of
stock receivable upon conversion thereof shall be paid by the person or persons
surrendering such stock for conversion.

             (k) Required Conversions. In the event that the volume weighted
average price (as determined using the AQR function on the Bloomberg terminal)
of the Corporation's Common Stock for all


                                       6
<PAGE>
trades during any consecutive eleven (11) day trading period on the Principal
Market is at a price greater than 118% of the Conversion Price, then the
Corporation may, at its sole option, provide the Holder irrevocable written
notice ("CALL NOTICE") within three (3) business days following such eleven (11)
day period requiring the conversion at the Conversion Price of all or a portion
of the Stated Value held by the Holder as of the date set forth in such Call
Notice (the "CALL DATE"), which such date shall be at least 11 trading days
following the date of the Call Notice, provided a registration statement
covering resales of that number of shares of Common Stock then issuable upon
conversion of this Preferred Stock pursuant to such Call Notice has been
declared effective and is available for use. The amount of Common Stock to be
issued in connection with any such conversion pursuant to a particular Call
Notice pursuant to this Section 5(k) shall not exceed 25% of the aggregate
dollar trading volume of the Common Stock for the 11 trading days immediately
preceding the Call Date. If the volume weighted average price (as determined
using the AQR function on the Bloomberg terminal) of the Common Stock for all
trades during such consecutive eleven (11) day trading period preceding the Call
Date falls below 118% of the Conversion Price, then the Holder will no longer be
required to convert the Preferred Stock pursuant to such Call Notice.


      6. Voting Rights. The shares of Series G Preferred Stock shall not have
voting rights.

      7. Events of Default.

      The occurrence of any of the following events of default (each, an "EVENT
OF DEFAULT") shall, after the applicable period to cure the Event of Default,
cause the then applicable Dividend Rate described in Section 3 hereof to become
20% from and after the occurrence of such event, and the Holder shall have the
option to require the Corporation to redeem the Series G Preferred Stock held by
such Holder by the immediate payment to the Holder by the Corporation of a sum
of money equal to 120% of the outstanding Stated Value, plus accrued and unpaid
dividends:

            7.1 Failure to Make Payment. The Corporation fails to pay any
payment required to be paid pursuant to the terms of hereof or the failure to
timely pay any other sum of money due to the Holder from the Corporation and
such failure continues for a period of three (3) days after written notice to
the Corporation from the Holder.

            7.2 Breach of Covenant. The Corporation breaches any material
covenant or other term or condition of this Certificate of Designations or the
Purchase Agreement in any material respect and such breach, if subject to cure,
continues for a period of five (5) days after written notice to the Corporation
from the Holder.

            7.3 Breach of Representations and Warranties. Any material
representation or warranty of the Corporation made herein, in the Purchase
Agreement, or in any agreement, statement or certificate given in writing
pursuant hereto or in connection therewith shall have been false or misleading
when made.

            7.4 Receiver or Trustee. The Corporation shall make an assignment
for the benefit of creditors, or apply for or consent to the appointment of a
receiver or trustee for it or for a substantial part of its property or
business; or such a receiver or trustee shall otherwise be appointed.

            7.5 Judgments. Except for judgments related to obligations of JMAR
Semiconductor, Inc., which are reflected on the Corporation's balance sheet, any
money judgment, writ or similar final process


                                       7
<PAGE>
shall be entered or filed against Corporation or any of its property or other
assets for more than $250,000, and shall remain unvacated, unbonded or unstayed
for a period of forty-five (45) days.

            7.6 Bankruptcy. Bankruptcy, insolvency, reorganization or
liquidation proceedings or other proceedings or relief under any bankruptcy law
or any law for the relief of debtors shall be instituted by or against the
Corporation.

            7.7 Stop Trade. An SEC stop trade order or Principal Market trading
suspension.

            7.8 Default Under Related Agreement. An Event of Default occurs
under and as defined in any one or more of the following agreements which is not
cured during any applicable cure or grace period: (i) Purchase and Security
Agreement dated March 21, 2003 between the Corporation, certain of its
subsidiaries, and Laurus Master Fund, Ltd., (ii) Securities Purchase Agreement
dated March 14, 2003 between the Corporation and Laurus Master Fund, Ltd., (iii)
Stock Pledge Agreement dated March 14, 2003 between the Corporation and Laurus
Master Fund, Ltd. and (iv) Pledge and Security Agreement dated March 14, 2003
between the Corporation and Laurus Master Fund, Ltd., as each such agreement may
be amended, modified and supplemented from time to time.

      8. Mandatory Redemption. In the event any shares of Series G Preferred
Stock are outstanding thirty six (36) months from the date of issuance thereof,
any remaining Stated Value of such shares shall be redeemed and such shares
shall be cancelled.

      9. Optional Redemption. The Corporation will have the option of redeeming
any outstanding amount of the Stated Value of the Preferred Stock ("OPTIONAL
REDEMPTION") by paying to the holder 118% of such amount, together with accrued
but unpaid dividends thereon and any and all other sums due, accrued or payable
to the holder arising under this certificate or any other document delivered
herewith ("REDEMPTION AMOUNT") outstanding on the day notice of redemption
("NOTICE OF REDEMPTION") is delivered to a holder ("REDEMPTION DATE"). A Notice
of Redemption may not be given in connection with any portion of Preferred Stock
for which a Notice of Conversion has been given by the holder at any time before
receipt of a Notice of Redemption or given pursuant to the following sentence.
The holder may elect within five (5) business days after receipt of a Notice of
Redemption to give the Corporation a Notice of Conversion in connection with
some or all of the amount which was the subject of the Notice of Redemption. The
Redemption Amount must be paid in good funds to the holder no later than the
seventh (7th) business day after the Redemption Date ("OPTIONAL REDEMPTION
PAYMENT DATE"). In the event the Corporation fails to pay the Redemption Amount
by the Optional Redemption Payment Date, then the Redemption Notice will be null
and void. A Notice of Redemption may be given by the Corporation, provided no
Event of Default shall have occurred or be continuing.

      10.   Amortization.

            (a) Monthly Payments. Subject to the terms of this Section 10, the
Corporation shall repay $37,500.00 of the original Stated Value of the Series G
Preferred Stock (to the extent such amount has not been converted pursuant to
Section 5 above), together with the dividend accrued to date on such portion of
the original Stated Value then due and payable (collectively the "MONTHLY
AMOUNT"), in accordance with Section 10(b) below, on the first business day of
each consecutive calendar month (each, a "REPAYMENT DATE"), beginning on January
3, 2005.


                                       8
<PAGE>
            (b) Cash or Common Stock. Subject to the terms hereof, the
Corporation has the sole option to determine whether to satisfy payment of the
Monthly Amount in full on each Repayment Date either in cash or in registered
shares of Common Stock, or a combination of both. The Corporation shall deliver
to the Holder a written irrevocable notice in the form of Exhibit B attached
hereto electing to pay such Monthly Amount in full on such Repayment Date in
either cash or registered Common Stock, or a combination of both ("REPAYMENT
ELECTION NOTICE"). Such Repayment Election Notice shall be delivered to the
Holder at least ten (10) days prior to the applicable Repayment Date (the date
of such notice being hereinafter referred to as the "NOTICE DATE"). If such
Repayment Election Notice is not delivered within the prescribed period set
forth in the preceding sentence, then the repayment shall be made in either cash
or shares of Common Stock on the same terms hereunder at the Holder's sole
option. If the Corporation elects or is required to repay all or a portion of
the Monthly Amount in cash on a Repayment Date, then on such Repayment Date the
Corporation shall pay to the Holder an amount equal to 102% of the Monthly
Amount in satisfaction of such obligation. If the Corporation repays all or a
portion of the Monthly Amount in shares of Common Stock, the number of such
shares to be issued for such Repayment Date shall be the number determined by
dividing (x) the portion of the Monthly Amount to be paid in shares of Common
Stock, by (y) the Conversion Price (as defined herein) as of such date.

            (c) No Effective Registration. Notwithstanding anything to the
contrary herein, the Corporation shall be prohibited from exercising its right
to repay the Monthly Amount in shares of Common Stock (and must deliver cash in
respect thereof) on the applicable Repayment Date if at any time from the Notice
Date until the time at which the Holder receive such shares there fails to exist
an effective registration statement or an Event of Default hereunder exists or
occurs, unless otherwise waived in writing by the Holder in whole or in part at
the Holder's option.

            (d) Share Price/Issuance Limitations. Notwithstanding anything to
the contrary herein, if the closing price of the Common Stock as reported by
Bloomberg, L.P. on the Principal Market for any of the 11 trading days preceding
a Repayment Date was less than 118% of the Conversion Price, and the Corporation
has elected to pay all or a portion of the Monthly Amount in shares of Common
Stock, then, in lieu of the Corporation delivering the required number of shares
of Common Stock on the Repayment Date, Corporation shall pay the Monthly Amount,
or the unconverted part thereof, in cash.

            (e) Deemed Conversions. Any repayment of the Monthly Amount in
 shares of Common Stock pursuant to the terms hereof shall constitute and be
 deemed a conversion of such portion of the applicable Stated Value of the
 Series G Preferred Stock for all purposes under this Certificate and the
 Purchase Agreement (as defined herein) (except as otherwise provided herein).

            (f) Deemed Ownership. In the case of the exercise of the conversion
 rights or payment of the Monthly Amount set forth herein the conversion
 privilege shall be deemed to have been exercised and the shares of Common Stock
 issuable upon such conversion or Repayment shall be deemed to have been issued
 upon the date of receipt by the Corporation of the Notice of Conversion or on
 the Repayment Date if the Monthly Amount is paid in shares of Common Stock, as
 the case may be. The person or entity entitled to receive Common Stock issuable
 upon such conversion shall, on the date such conversion privilege is deemed to
 have been exercised and thereafter, be treated for all purposes as the record
 holder of such Common Stock.

      11. Status of Converted or Redeemed Stock. In case any shares of Series G
Preferred Stock shall be redeemed or otherwise repurchased or reacquired, the
shares so redeemed, converted, or reacquired shall resume the status of
authorized but unissued shares of Preferred Stock and shall no longer be
designated as Series G Preferred Stock.

      In witness whereof, JMAR Technologies, Inc. has caused this Certificate to
be executed by Joseph G.


                                       9
<PAGE>
Martinez, its Senior Vice President and General Counsel, this 5th day of
February, 2004.


                              JMAR TECHNOLOGIES, INC.


                              By: /s/ JOSEPH G. MARTINEZ


                                       10
<PAGE>
                                    EXHIBIT A

                              NOTICE OF CONVERSION

(To Be Executed By the Registered Holder in Order to Convert the Series G
Convertible Preferred Stock of JMAR Technologies, Inc.)

      The undersigned hereby irrevocably elects to convert ______________ shares
of Series G Convertible Preferred Stock and $_____________ of the dividend due,
into shares of Common Stock of JMAR Technologies, Inc. (the "Corporation")
according to the conditions hereof, as of the date written below.

Date of Conversion:_____________________________________________________________

Applicable Conversion Price Per Share:__________________________________________



Number of Common Shares Issuable Upon This Conversion:_________________



Signature:______________________________________________________________________

Print Name:_____________________________________________________________________

Address:________________________________________________________________________

________________________________________________________________________________

Deliveries Pursuant to this Notice of Conversion Should Be Made to:

________________________________________________________________________________

________________________________________________________________________________

________________________________________________________________________________



                                       11
<PAGE>
                                    EXHIBIT B

                        FORM OF REPAYMENT ELECTION NOTICE


To:   [HOLDER AT HOLDER'S ADDRESS]

      Pursuant to Section 10(b) of the Certificate to Set Forth Designations of
Series G Convertible Preferred Stock ("Preferred Stock") of JMAR Technologies,
Inc. issued on February 5, 2004, we hereby notify you that we are irrevocably
electing to repay the outstanding Monthly Amount (as defined in the Preferred
Stock) due on the Repayment Date (as defined in the Preferred Stock) which
occurs on ________, 20___ (CHECK ONE):


      _____ In full in cash on such Repayment Date.

      _____ In full in shares of the Company's Common Stock within three (3)
            trading days following such Repayment Date.

      _____ In part in
            cash in the amount of $ _____ on such Repayment Date, and in part in
            shares of the Company's Common Stock (in the amount of _____ shares)
            within three (3) trading days following such Repayment Date.


                                          JMAR Technologies, Inc.

                                          By: _______________________
                                          Name:
                                          Title:


                                       12