<PAGE>

                                                                   EXHIBIT 10(a)

THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE "ACT"),
AND HAS BEEN ISSUED UNDER AN EXEMPTION PURSUANT TO REGULATION S UNDER THE ACT.
UNTIL ONE YEAR AFTER THE DATE OF THIS NOTE, NO AMOUNT OF THE NOTE MAY BE
OFFERED, SOLD, OR TRANSFERRED TO ANY U.S. PERSON. OFFERS, SALES OR TRANSFERS IN
THE U.S. OR TO A U.S. PERSON (AS DEFINED IN REGULATION S PROMULGATED UNDER THE
ACT) OR FOR THE ACCOUNT AND BENEFIT OF A U.S. PERSON ARE NOT PERMITTED, EXCEPT
AS PROVIDED IN SAID REGULATION S, UNLESS THE SHARES ARE REGISTERED UNDER THE ACT
OR AN EXEMPTION FROM SUCH REGISTRATION UNDER THE ACT IS APPLICABLE.

                                                        PRINCIPAL AMOUNT
                                                   ============================
                                                           $75,000  (U.S.)
                                                   ============================

                             POWER TECHNOLOGY, INC.

                            SERIES A CONVERTIBLE NOTE

                         MATURITY DATE: JANUARY 28, 2001


          1.   PAYMENT OF PRINCIPAL. Power Technology, Inc., a corporation
organized and registered under the laws of the State of Nevada (the
"Company"), for value received, hereby promises to pay to the order of
Dorotea Kleva, or the registered holder of this Note, if different, the
Principal Amount hereof on the Maturity Date of January 28, 2001, as provided
herein. This Note bears interest at ten percent (10%) per annum, payable in
the Common Stock of the Company at the rate of $.50 per share.

          2.   PRE-PAYMENT RIGHTS; POSSIBLE REPURCHASE. The Company has no
right to pre-pay this Note prior to January 28, 2001. The registered holder
hereof may present this Note to the Company for repurchase upon written
request at a price and at terms to be negotiated at the time of the request.
However, the Company has no obligation to repurchase this Note. The decision
to repurchase this Note shall be within the sole discretion and business
judgment of the Company.

          3.   CONVERSION. The principal amount of this Note may be converted
into the Common Stock of the Company at the option of the holder of this
Note, upon written notice to the Company, at $0.50 (U.S.) per share, subject
to adjustment in the event of stock-splits, stock dividends, reorganizations,
or other similar events to prevent dilution. Upon conversion, any fractional
shares otherwise issuable upon conversion shall be paid in cash by the
Company.

          4.   TRANSFER. This Note will be transferable only upon the
surrender of this Note for registration of transfer, the delivery of such
other documents and information as the Company may reasonably require from
the transferor and/or transferee, and compliance with applicable federal and
state securities laws.

          5.   GOVERNING LAW. This Note will be governed by, and construed in
accordance with, the laws of the State of Nevada, but without giving effect
to applicable principles of conflicts of law to the extent that the
application of the law of another jurisdiction would be required.

          6.   REPORTS TO NOTE HOLDERS. The Company will regularly mail to
the registered holder of this Note copies of its annual report to shareholders
containing its certified financial statements, and other financial reports that
the Company provides to its shareholders.

<PAGE>


          7.   NOTICES. All notices, demands or other writings in this Note
provided to be given or made or sent shall be deemed to have been fully given
or made or sent when made in writing and deposited in the United States mail,
registered and postage prepaid, and addressed to the Company at 1000 W.
Bonanza Road, Las Vegas, Nevada 89102, and to the registered holder of this
Note at its registered address.

          8.   TIME OF THE ESSENCE. Time is of the essence of each part of
this Note.

          9.   VALIDITY. Should any portion of this Note be declared invalid
and unenforceable by a duly authorized entity, then such portion shall be
severable from this Note and shall not affect the remainder thereof.

          10.  SURVIVAL OF RIGHTS. This Note shall be binding upon and shall
inure to the benefit of the Company, the registered holder hereof and their
respective heirs, legatees, legal representatives, successors and assigns.

          11.  ENTIRE AGREEMENT. There are no verbal understandings between
the Company and the registered holder of this Note. This Note shall not be
changed, modified or altered unless the changes, modifications or alterations
are in writing and executed and agreed to by the Company and the registered
holder of this Note.

          12.  WAIVER. No waiver by the registered holder hereof of any
payment or other right under this Note or any related agreement or
documentation shall operate as a waiver of any other payment or right.

          13.  CAPTIONS. The captions appearing in this Note are for
convenience only, and are not a part of this Note and do not, in any way,
limit or amplify the terms and provisions of this Agreement.

          IN WITNESS WHEREOF, the Company has caused this Note to be duly
executed under its corporate seal.

                                                   POWER TECHNOLOGY, INC.
ATTEST:                             (SEAL)


By:                                                By: /s/ Lee A. Balak
   ----------------------------------                 ------------------------
               Secretary                               Lee A. Balak, President


                                       2
<PAGE>


                                   ASSIGNMENT



               FOR VALUE RECEIVED, ________________________________ (SSN or
FEIN: __________________) hereby sell, assign and transfer unto ________________
__________________________ whose address is ____________________________________
______________________________ and whose SSN or FEIN is ___________________ this
Note and do hereby irrevocably constitute and appoint Power Technology, Inc. to
transfer said Note on the books of the Company, with full power of substitution
in the premises.

               DATED ______________________, 200___.


                                           -------------------------------------


                                           -------------------------------------


SIGNATURE GUARANTEE:


-----------------------------------



-----------------------------------





NOTICE:        Signature guarantee must be made by a national bank, registered
               broker-dealer, Stamp or other approved signature guarantee
               program acceptable to the Securities and Exchange Commission,
               the Securities Transfer Association and the transfer agent of
               the Company.


                                       3

<PAGE>

THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE
"ACT"), AND HAS BEEN ISSUED UNDER AN EXEMPTION PURSUANT TO REGULATION S UNDER
THE ACT. UNTIL ONE YEAR AFTER THE DATE OF THIS WARRANT, NO PART OF THIS WARRANT
MAY BE OFFERED, SOLD, OR TRANSFERRED TO ANY U.S. PERSON. OFFERS, SALES OR
TRANSFERS IN THE U.S. OR TO A U.S. PERSON (AS DEFINED IN REGULATION S
PROMULGATED UNDER THE ACT) OR FOR THE ACCOUNT AND BENEFIT OF A U.S. PERSON ARE
NOT PERMITTED, EXCEPT AS PROVIDED IN SAID REGULATION S, UNLESS THE WARRANT IS
REGISTERED UNDER THE ACT OR AN EXEMPTION FROM SUCH REGISTRATION UNDER THE ACT IS
APPLICABLE.

                          COMMON STOCK PURCHASE WARRANT

                             Dated January 28, 2000
                      ------------------------------------


                           Void After January 28, 2001

                  Power Technology, Inc. (the "Company"), a Nevada
corporation, hereby certifies that, for value received, Dorotea Kleva, or
registered assigns (hereinafter referred to as the "Warrantholders"), is
entitled, subject to the terms and conditions set forth in this Warrant (said
Warrant and any warrants issued in exchange or transfer or replacements hereof
being hereinafter collectively referred to as the "Warrants"), to purchase
from the Company, for cash, One Hundred Fifty Thousand (150,000) fully paid
and nonassessable shares of Common Stock of the Company, $.001 par value (the
"Common Stock," which term is further defined in Paragraph IV C. hereof), at
any time or from time to time until 5 p.m. Nevada local time on January 28,
2001, at an exercise price of Sixty Cents ($.60 U.S.) per share (the "Exercise
Price"), the number of such shares of Common Stock and the Exercise Price
being subject to adjustment as provided herein.

         I.       EXERCISE OF WARRANT. The rights represented by this Warrant
may be exercised by the Warrantholders, in whole or in part (but not as to a
fractional share of Common Stock), by the presentation and surrender of this
Warrant with written notice of Warrantholders' election to purchase, at the
principal executive office of the Company, or at such other address as the
Company may designate by notice in writing to the Warrantholders at the
address of such Warrantholders appearing on the books of the Company, and upon
payment to the Company of the Exercise Price for such shares of Common Stock.
Such payment shall be made by certified or cashier's check payable to the
order of the Company. The Company agrees that the shares so purchased (the
"Warrant Shares") shall be deemed to have been issued to the Warrantholders as
the record owner of such Warrant Shares as of the close of business on the
date on which this Warrant shall have been surrendered together with the
aforementioned written notice of election to purchase, and payment for such
Warrant Shares shall have been made as aforesaid. Certificates for the Warrant
Shares so purchased shall be delivered to the Warrantholders within a
reasonable time, not exceeding five (5) days, after the rights represented by
this Warrant shall have been so exercised, and, unless this Warrant has
expired, a new Warrant representing the number of shares, if any, with respect
to which this Warrant shall not then have been exercised shall also be issued
to the Warrantholders within such time.

         II.      EXERCISE PRICE. Warrant Shares shall be purchased at the
Exercise Price set forth above, subject to adjustment as provided herein.

<PAGE>

         III.     WARRANTHOLDERS NOT DEEMED STOCKHOLDERS. Subject to the
provisions of the Company's Restated Articles of Incorporation and By-Laws,
copies of which will be delivered to the Warrantholders upon request, the
Warrantholders shall not be entitled to vote or receive dividends or be deemed
the holders of Common Stock, nor shall anything contained herein be construed
to confer upon the Warrantholders, as holders of Warrants, any of the rights
of a stockholder of the Company or any right to vote upon any matter submitted
to stockholders at any meeting thereof, or to give or withhold consent to any
corporate action (whether upon any recapitalization, issue of stock,
reclassification of stock, change of par value or change of stock to no par
value, consolidation, merger, conveyance, or otherwise) or to receive notice
of meetings, or to receive dividends, except as otherwise provided herein,
until this Warrant shall have been duly exercised and the Warrant Shares
receivable upon the exercise hereof shall have become deliverable as provided
in Paragraph I above.

         IV.      ADJUSTMENT OF NUMBER OF SHARES, EXERCISE PRICE AND NATURE OF
SECURITIES ISSUABLE UPON EXERCISE OF WARRANTS.

                  A. STOCK DIVIDEND, RECAPITALIZATION, MERGER, ETC. If and
whenever after the date hereof (i) any change occurs in the outstanding shares
of any class or series of Common Stock by reason of any stock dividend, stock
split, recapitalization, consolidation or merger; or (ii) the Company pays any
distribution or dividend in cash or property of the Company, the holder of
this Warrant shall thereafter, upon exercise of this Warrant, be entitled to
receive the number of shares of stock or other securities or the cash or
property of the Company (or of the successor corporation resulting from any
consolidation or merger) to which the shares of Common Stock (and any other
securities) deliverable upon the exercise of this Warrant would have been
entitled if this Warrant had been exercised immediately prior to the earlier
of (i) such event, and (ii) the record date, if any, set for determining the
holders entitled to participate in such event and the Exercise Price shall be
adjusted appropriately so that the aggregate amount payable by the holder
hereof upon the full exercise of this Warrant remains the same. The Company
shall not effect any recapitalization, consolidation or merger unless, upon
the consummation thereof, the successor corporation shall assume by written
instrument the obligation to deliver to the holder hereof such shares of
stock, securities, cash or property as such holder shall be entitled to
purchase in accordance with the foregoing provisions.

                     If pursuant to the provisions of this Paragraph IV A. the
holder of this Warrant would be entitled to receive shares of stock or other
securities upon the exercise of this Warrant in addition to the shares of
Common Stock issuable upon exercise of this Warrant, the Company shall at all
times reserve and keep available sufficient shares or other securities to
permit the Company to issue such additional shares or other securities upon
the exercise of this Warrant. If pursuant to the provisions of this Paragraph
I A. the holder of this Warrant would be entitled to receive cash or property
upon the exercise of this Warrant, the Company shall set aside and hold in
trust as the property of the holder of this Warrant a sufficient amount of
such cash or property to permit payment in full of all such cash or property
that would be payable upon the exercise of this Warrant.


                                        2
<PAGE>

                  B. ACCOUNTANTS' CERTIFICATE. In each case of an adjustment
in the number of shares of Common Stock or other stock, securities or property
receivable on the exercise of the Warrants, the Company at its expense shall
cause independent public accountants of recognized standing selected by the
Company and acceptable to the Warrantholders to compute such adjustment in
accordance with the terms of this Warrant and prepare a certificate setting
forth such adjustment and showing in detail the facts upon which such
adjustment is based, including a statement of (a) the consideration received
or to be received by the Company for any additional shares of Common Stock,
rights, options or convertible securities issued or sold or deemed to have
been issued or sold, (b) the number of shares of Common Stock of each class
and/or series outstanding or deemed to be outstanding, (c) the adjusted
Exercise Price and (d) the number of shares issuable upon exercise of this
Warrant. The Company will forthwith mail a copy of each such certificate to
each Warrantholder.

                  C. DEFINITION OF COMMON STOCK. As used herein, the term
"Common Stock" shall mean and include the Company's authorized common stock of
any class, classes or series, and shall also include any capital stock of any
class or series of the Company hereafter authorized which shall not be limited
to a fixed sum or percentage of par value in respect of the rights of the
holders thereof to participate in dividends and in the distribution of assets
upon the voluntary or involuntary liquidation, dissolution or winding up of
the Company, and shall include any common stock of any class, classes or
series resulting from any reclassification or reclassifications thereof.

         V.       Special Agreements of the Company.

                  A. RESERVATION OF SHARES. The Company covenants and agrees
that all Warrant Shares will, upon issuance, be validly issued, fully paid and
nonassessable and free from all preemptive rights of any stockholder, and from
all taxes, liens and charges with respect to the issue thereof (other than
taxes in respect to any transfer occurring contemporaneously with such issue).
The Company further covenants and agrees that during the period within which
the rights represented by this Warrant may be exercised, the Company will at
all times have authorized, and reserved, a sufficient number of shares of
Common Stock to provide for the exercise of the rights represented by this
Warrant.

                  B. AVOIDANCE OF CERTAIN ACTIONS. The Company will not, by
amendment of its Certificate of Incorporation or through any reorganization,
transfer of assets, consolidation, merger, issue or sale of securities or
otherwise, avoid or take any action which would have the effect of avoiding
the observance or performance of any of the terms to be observed or performed
hereunder by the Company, but will at all times in good faith assist in
carrying out all of the provisions of this Warrant and in taking all of such
action as may be necessary or appropriate in order to protect the rights of
the Warrantholders against dilution as provided herein or other impairment of
their rights hereunder.

                  C. COMMUNICATION TO SHAREHOLDERS. Any notice, document or
other communication given or made by the Company to holders of Common Stock as
such shall at the same time be provided to the Warrantholders.


                                        3
<PAGE>

                  D. COMPLIANCE WITH LAW. The Company shall comply with all
applicable laws, rules and regulations of the United States and of all states,
municipalities and agencies and of any other jurisdiction applicable to the
Company and shall do all things necessary to preserve, renew and keep in full
force and effect and in good standing its corporate existence and authority
necessary to continue its business.

         IV.      Fractional Shares. No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this
Warrant. With respect to any fraction of a share called for upon exercise
hereof, the Company shall pay to the Warrantholder an amount in cash equal to
such fraction multiplied by the current fair value of one share of Common
Stock.

         VII.     NOTICES OF STOCK DIVIDENDS, SUBSCRIPTIONS,
RECLASSIFICATIONS, CONSOLIDATIONS, MERGERS, ETC. If at any time: (i) the
Company shall declare a cash dividend (or an increase in the then existing
dividend rate), or declare a dividend on Common Stock payable otherwise than
in cash out of its net earnings after taxes for the prior fiscal year; or (ii)
the Company shall authorize the granting to the holders of Common Stock of
rights to subscribe for or purchase any shares of capital stock of any class
or of any other rights; or (iii) there shall be any capital reorganization, or
reclassification, or redemption of the capital stock of the Company, or
consolidation or merger of the Company with, or sale of all or substantially
all of its assets to, another corporation or firm; or (iv) there shall be a
voluntary or involuntary dissolution, liquidation or winding up of the
Company, then the Company shall give to the Warrantholders at the addresses of
such Warrantholders as shown on the books of the Company, at least twenty (20)
days prior to the applicable record date hereinafter specified, a written
notice summarizing such action or event and stating the record date for any
such dividend or rights (or, if a record date is not to be selected, the date
as of which the holders of Common Stock of record entitled to such dividend or
rights are to be determined), the date on which any such reorganization,
reclassification, consolidation, merger, sale of assets, dissolution,
liquidation or winding up is expected to become effective, and the date as of
which it is expected the holders of Common Stock of record shall be entitled
to effect any exchange of their shares of Common Stock for cash (or cash
equivalent) securities or other property deliverable upon any such
reorganization, reclassification, consolidation, merger, sale of assets,
dissolution, liquidation or winding up.

         VIII.    REGISTERED HOLDER; TRANSFER OF WARRANTS OR WARRANT SHARES.

                  A. MAINTENANCE OF REGISTRATION BOOKS; OWNERSHIP OF THIS
WARRANT. The Company shall keep at its principal office a register in which,
subject to such reasonable regulations as it may prescribe, the Company shall
provide for the registration, transfer and exchange of this Warrant. The
Company shall not at any time, except upon the dissolution, liquidation or
winding-up of the Company, close such register so as to result in preventing
or delaying the exercise or transfer of this Warrant.

                        The Company may deem and treat the person in whose
name this Warrant is registered as the holder and owner hereof (notwithstanding
any notations of ownership or writing hereon made by anyone other than the
Company) for all purposes and shall not be affected by any notice to the
contrary, until presentation of this Warrant for registration or transfer


                                        4
<PAGE>

as provided in this Paragraph VIII.

                  B. EXCHANGE AND REPLACEMENT. This Warrant is exchangeable
upon surrender hereof by the registered holder to the Company at its principal
office for new Warrants of like tenor and date representing in the aggregate
the right to purchase the number of shares purchasable hereunder, each of such
new Warrants to represent the right to purchase such number of shares as shall
be designated by said registered holder at the time of surrender. Subject to
compliance with the provisions of Paragraphs VIII and IX, this Warrant and all
rights hereunder are transferable in whole or in part upon the books of the
Company by the registered holder hereof in person or by duly authorized
attorney, and a new Warrant shall be made and delivered by the Company, of the
same tenor and date as this Warrant but registered in the name of the
transferee, upon surrender of this Warrant, duly endorsed, to said office of
the Company. Upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant, and upon
surrender and cancellation of this Warrant, if mutilated, the Company will
make and deliver a new Warrant of like tenor, in lieu of this Warrant, upon
the delivery of an appropriate bond if required by the Company. This Warrant
shall be promptly canceled by the Company upon the surrender hereof in
connection with any exchange, transfer or replacement. The Company shall pay
all expenses, taxes and other charges payable in connection with the
preparation, execution and delivery of Warrants pursuant to this Paragraph
VIII.

                  C. WARRANTS AND WARRANT SHARES NOT REGISTERED. The holder of
this Warrant, by accepting this Warrant, represents and acknowledges that this
Warrant and the Warrant Shares have not been registered under the Securities
Act on the grounds that the issuance of this Warrant and the offering and sale
of such Warrant Shares were exempt from registration under Regulation S of the
Securities Act.

         IX.      MISCELLANEOUS PROVISIONS.

                  (a) GOVERNING LAW AND VENUE. This Warrant shall be deemed to
have been made in the State of Nevada and the validity of this Warrant, the
construction, interpretation, and enforcement thereof, and the rights of the
parties thereto shall be determined under, governed by, and construed in
accordance with the internal laws of the State of Nevada, without regard to
principles of conflicts of law. The parties agree that all actions or
proceedings arising in connection with this Warrant shall be tried and
litigated only in the state or federal courts located in the State of Nevada
or, at the sole option of a Warrantholder, in any other court in which a
Warrantholder shall initiate legal or equitable proceedings and which has
subject matter jurisdiction over the matter in controversy. The Warrantholders
and the Company each waive the right to a trial by jury and any right each may
have to assert the doctrine of FORUM NON CONVENIENS or to object to venue to
the extent any proceeding is brought in accordance with this Paragraph IX(a).
Service of process, sufficient for personal jurisdiction in any action against
the Company, may be made by registered or certified mail, return receipt
requested, to its address indicated in Paragraph IX A.

                  A. NOTICES. All notices hereunder shall be in writing and
shall be deemed to have been given one (1) business day after being sent by
facsimile or five (5) days after being mailed by certified mail, addressed to
the address below stated of the party to which notice is given, or to such


                                        5
<PAGE>

changed address as such party may have fixed by notice:

         To the Company:                  Power Technology, Inc.
                                          1000 W. Bonanza Road
                                          Las Vegas, Nevada 99105

         To the Warrantholders            At the addresses of such holders as
         or holder of                     they appear on the records of the
         Warrant Shares                   Company

provided, however, that any notice of change of address shall be effective only
upon receipt.

                  B. ASSIGNMENT. This Warrant shall be binding upon and inure
to the benefit of the Company, the Warrantholders and the holders of Warrant
Shares and the successors, assigns and transferees of the Company, the
Warrantholders and the holders of Warrant Shares.

                  C. ATTORNEYS' FEES. If any legal action or any arbitration
or other proceeding is brought for the enforcement of this Warrant, or because
of an alleged dispute, breach, default, or misrepresentation in connection
with any of the provisions of this Warrant, the successful or prevailing party
or parties shall be entitled to recover such reasonable attorneys' fees and
other costs incurred in that action or proceeding, in addition to any other
relief to which it or they may be entitled, as may be ordered in connection
with such proceeding.

                  D. ENTIRE AGREEMENT; AMENDMENTS AND WAIVERS. This Warrant
sets forth the entire understanding of the parties with respect to the
transactions contemplated hereby. The failure of any party to seek redress for
the violation or to insist upon the strict performance of any term of this
Warrant shall not constitute a waiver of such term and such party shall be
entitled to enforce such term without regard to such forbearance. This Warrant
may be amended, the Company may take any action herein prohibited or omit to
take action herein required to be performed by it, and any breach of or
compliance with any covenant, agreement, warranty or representation may be
waived, only if the Company has obtained the written consent or written waiver
of the majority in interest of the Warrantholders, and then such consent or
waiver shall be effective only in the specific instance and for the specific
purpose for which given.

                  E. SEVERABILITY. If any term of this Warrant as applied to
any person or to any circumstance is prohibited, void, invalid or
unenforceable in any jurisdiction, such term shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or invalidity without in any
way affecting any other term of this Warrant or affecting the validity or
enforceability of this Warrant or of such provision in any other jurisdiction.

                  F. HEADINGS. The headings in this Warrant are inserted only
for convenience of reference and shall not be used in the construction of any
of its terms.


                                        6
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this Warrant to be signed
by its duly authorized officers on the date first written above.

                                               POWER TECHNOLOGY, INC.
                                               a Nevada corporation


                                               By:   /s/ Lee A. Balak
                                                   --------------------
                                                       Lee A. Balak, President

Attest:    [SEAL]

---------------------------
                Secretary














                                        7