<PAGE>

EX-10.30
Convertible Promissory Note Issued to an Individual


                                  EXHIBIT 10.30


                       FORM OF CONVERTIBLE PROMISSORY NOTE


THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"). THESE SECURITIES
HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH,
THE DISTRIBUTION THEREOF. THESE SECURITIES MAY NOT BE OFFERED, SOLD, PLEDGED, OR
TRANSFERRED UNLESS (I) A REGISTRATION STATEMENT UNDER THE SECURITIES ACT IS IN
EFFECT AS TO THESE SECURITIES OR (II) THERE IS AN OPINION OF COUNSEL, REASONABLY
SATISFACTORY TO THE CORPORATION, THAT AN EXEMPTION THEREFROM IS AVAILABLE.

THIS CONVERTIBLE PROMISSORY NOTE IS SUBJECT TO TRANSFERABILITY RESTRICTIONS
PURSUANT TO SECTION 7 HEREIN AND SHALL NOT BE TRANSFERRED BY THE COMPANY UNLESS
THE HOLDER HEREOF COMPLIES THEREWITH. ANY ATTEMPTED TRANSFER OF SECURITIES NOT
IN COMPLIANCE WITH SUCH SECTION 7 SHALL BE NULL AND VOID.

                               TELEGEN CORPORATION

                           Convertible Promissory Note

US$225,000                                              Redwood City, California
                                                                   July 24, 1998

     FOR VALUE RECEIVED, TELEGEN CORPORATION, a California corporation (together
with its successors and assigns, the "Company"), promises to pay to the order of
R. S. Kripalani (the "Holder"), (i) an amount (the "Face Value") of US$225,000
plus (ii) simple interest on the unpaid balance at the time such interest is
due. Interest on this Note shall be paid at a rate equal to Six Percent (6%) per
annum and shall be payable one year from the date hereof. Payment of all amounts
due hereunder shall be made by wire transfer, subject to adjustment in certain
events as more fully set forth in Section 2 herein.

     This Note is issued pursuant to that certain Satisfaction and Release
Agreement dated as of July 24, 1998 (the "Agreement"), between the Company and
the Holder.

     The following is a statement of the rights of the Holder and the conditions
to which this Note is subject, to which the Holder, by acceptance of this Note,
hereby agrees:

     1. REPAYMENT OBLIGATION.

          (a) REPAYMENT. The Company shall be required to repay all principal
and any outstanding interest on this Note in full one (1) year from the date
hereof (the "Repayment Obligation"). The Company shall be entitled to prepay any
portion of the principal or interest at any time before this Note is due in full
after giving the Holder 15 days written notice. During such period, the Holder
shall be entitled to convert this note in accordance with Section 2 herein.

          (b) ADJUSTMENT IN NOTE'S FACE VALUE. Upon any prepayment by the
Company of this Note, the Company will on its books and records reduce the face
value of this Note and send notice of such change to the Holder hereof. To the
extent the Note 's face value is greater than zero on the Company's books and
records, the Company will upon request by the Holder hereof, deliver, a new Note
of like tenor in the principal amount remaining on such Note.

<PAGE>

     2. CONVERSION.

          (a) CONVERSION. Holder shall have the right to convert at any time, in
whole or in part, any portion of outstanding principal or interest on the Note
(a "Portion") to the Company's Common Stock by (i) surrender of this Note,
together with (ii) an executed Notice of Conversion, substantially in the form
of EXHIBIT A attached hereto, at the Company's Principal Executive Office. The
number of shares of Common Stock into which any Portion may be converted shall
be determined by dividing the dollar amount of such Portion by $0.38 (the
"Conversion Price"). No fractional shares or scrip representing fractions of
shares will be issued on conversion, and the number of shares issuable shall be
rounded down to the nearest whole share. The shares of Common Stock issued or
issuable upon conversion of this Note are referred to herein as the "Shares."

          (b) ISSUANCE OF SECURITIES ON CONVERSION. Conversion of this Note, in
whole or in part, shall occur if the Holder elects to convert under Section 2(a)
above. Upon exercise of all or part of this Note by the Holder, and unless a
registration statement covering the issuance of the underlying Common Stock is
on file with the Commission and currently effective, the Holder shall confirm in
writing, by executing the form attached hereto as EXHIBIT B, that the shares of
Common Stock purchased thereby are being acquired for investment, solely for the
Holder's own account and not as a nominee for any other Person, and not with a
view toward distribution or resale. As soon as practicable after conversion of
all or part of this Note, the Company at its expense will cause to be issued, in
the name of and delivered to the Holder at the Holder's registered address, a
certificate for the number of shares of the Company's capital stock to which the
Holder shall be entitled on such conversion and a note with identical terms and
conditions as this Note except that the face value of such note shall be for the
outstanding face value of this Note, if any, after conversion hereof. Such
certificate and such note will bear such legends as may be required by
applicable state and federal securities laws in the opinion of legal counsel for
the Company.

          (c) ADJUSTMENT IN CONVERSION PRICE. The Conversion Price shall be
proportionately adjusted upon a reorganization, reclassification, which
substantially affects the Company's entire capital stock, or a stock split or
similar transaction (an "Adjustment Transaction"). The issuance of additional
capital stock, securities which are convertible to the Company's capital stock
(including but not limited to warrants and convertible notes) or the issuance of
capital stock upon conversion of any such convertible securities shall not
constitute an Adjustment Transaction.

     3. RESTRICTIONS ON TRANSFER.

          (a) LEGENDS. Each certificate representing the Shares may be endorsed
with the following legends, and the Holder may not make any transfer of any of
the Shares without first complying with the restrictions on transfer described
in all such legends:

               (i) The 1933 Securities Act legend set forth on the face of this
Note.

               (ii) Any other legends required by applicable state securities
laws.

The Company need not register a transfer of any Shares, and may also instruct
its transfer agent not to register the transfer of such Shares, unless the
conditions specified in this Section 3 are satisfied.

          (b) REMOVAL OF LEGEND AND TRANSFER RESTRICTIONS.

               (i) Any legend endorsed on a certificate pursuant to Section
3(a)(i) and any stop transfer instructions with respect to the Shares evidenced
by such certificate shall be removed and the Company shall issue a certificate
without such legend to the holder thereof if such Shares are registered upon
issuance under the Securities Act, and if such legend may be properly removed
under the terms of Rule 144 promulgated under the Securities Act, or if such
holder provides the Company with an opinion of counsel for such holder
reasonably satisfactory to legal counsel for the Company, to the effect that a
sale, transfer or assignment of such shares may be made without registration.

               (ii) Any legend endorsed on a certificate pursuant to Section
3(a)(ii) and the stop transfer instructions with respect to the Shares evidenced
by such certificate shall be removed upon receipt by the Company of an order of
the appropriate state securities authority authorizing such removal.

     4. PREPAYMENT. The Company may prepay this Note, in whole or in part, in
accordance with Section 1(a) herein.

     5. EVENTS OF DEFAULT; ACCELERATION.

<PAGE>

          (a) So long as this Note is unpaid, each of the following events will
constitute an "Event of Default":

               (i) default in the payment of the principal or interest of this
Note as and when the same shall become due and payable at maturity, by
declaration or otherwise, and continuance of such default for a period of five
days; or

               (ii) an involuntary case or other proceeding shall be commenced
against the Company seeking liquidation, reorganization or other relief with
respect to it or its debts under any applicable bankruptcy, insolvency or other
similar law now or hereafter in effect, or seeking the appointment of a
receiver, liquidator, assignee, custodian, trustee, sequestrator (or similar
official) of the Company or for any substantial part of the property of the
Company or the winding up or liquidation of the affairs of the Company, and such
case or proceeding shall remain unstayed and undismissed for a period of 60
days, or an order for relief shall be entered against the Company under the
federal bankruptcy laws as now or hereafter in effect; or

               (iii) the Company shall commence a voluntary case under any
applicable bankruptcy, insolvency or other similar law now or hereafter in
effect, or consent to the entry of an order for relief in an involuntary case
under any such law, or consent to the appointment or taking possession by a
receiver, liquidator, assignee, custodian, trustee, sequestrator (or similar
official) of the Company or for any substantial part of the property of the
Company, or the Company shall make any general assignment for the benefit of
creditors, or shall fail generally to pay its debts as they come due, or shall
take any corporate action to authorize any of the foregoing; or

               (iv) failure on the part of the Company to observe or perform any
of the covenants contained in this Note (other than a failure to make a payment
specified in clause (i) above) or in the Agreement and the continuance of such
failure for a period of 30 days following receipt of notice from the Holder
specifying such covenant and the nature of the Company's non-performance.

          (b) If an Event of Default shall occur, then the Holder may by notice
to the Company (a "Default Notice"), so long as the Event of Default exists, (i)
declare the unpaid principal and accrued interest, if any, of this Note
immediately due and payable without further presentment, demand, protest, or
notice, all of which are hereby waived, and (ii) be entitled from the date of
Event of Default to an additional 2% simple interest on outstanding principal of
this Note.

     6. NOTICES. Any notice, request, or other communications required or
permitted hereunder shall be in writing and shall deemed to have been duly given
if sent by facsimile, or mailed by registered or certified mail, postage
prepaid, or by recognized overnight courier or personal delivery, addressed (a)
if to the Holder, to it at the last known address appearing on the books of the
Company maintained for such purpose, or (b) if to the Company, to it at 101
Saginaw Drive, Redwood City, California 94063, attention: Chief Executive
Officer, telephone (650) 261-9400, facsimile (650) 261-9468, with a copy (which
will not constitute notice) to Thomas C. DeFilipps, Esq., Wilson Sonsini
Goodrich & Rosati, 650 Page Mill Road, Palo Alto, California 94304, telephone
(650) 493-9300, facsimile (650) 493-6811. Any party hereto may by notice so
given change its address for future notice hereunder. All such notices will be
deemed to have been given (i) upon confirmation of delivery, if sent by
facsimile or (ii) upon delivery, if sent by courier or personal delivery.

     7. TRANSFERABILITY. With respect to any offer, sale or other disposition of
any of this Note or the Shares (collectively, the "Securities"), the Holder will
give written notice to the Company prior thereto, describing briefly the manner
thereof, and, if requested by the Company, a written opinion of the Holder's
counsel to the effect that such offer, sale or other distribution may be
effected without registration or qualification under any federal or state law
then in effect or necessary compliance with any other transferability
restrictions relating thereto . Promptly upon receiving such written notice and
reasonably satisfactory opinion, if so requested, the Company, as promptly as
practicable, shall notify the Holder that the Holder may sell or otherwise
dispose of such Securities. Subject to compliance with applicable state and
federal law and the terms of the notice delivered to the Company, the Holder may
transfer such Securities only by surrendering them to the Company with a duly
executed Assignment Form, substantially in the form attached hereto as EXHIBIT C
and funds sufficient to pay any transfer tax, whereupon the Company will cancel
such Securities and execute and deliver one or more new Securities in the names
and amounts specified in such instrument and, if the Holder's entire interest in
such Securities is not being assigned, in the name of the Holder for the balance
of such interest, unless otherwise specified in the Assignment Form. Any Note
issued upon transfer of this Note shall bear the legends on the face of this
Note. All certificates representing Shares delivered upon transfer of Securities
shall bear the legends required by Section 3. If a determination has been made
pursuant to this Section 7 that the opinion of counsel for the

<PAGE>

Holder is not reasonably satisfactory to the Company, the Company shall so
notify the Holder promptly after such determination has been made. Any attempted
transfer of Securities not in compliance with this Section 7 shall be null and
void.

     8. ASSIGNMENT. The rights and obligations of the Company and the Holder
shall be binding upon and benefit the successors, assigns, heirs,
administrators, and transferees of the parties. The Holder may assign his rights
and obligations hereunder subject to Sections 3 and 7 of this Note. This
provision shall in no way affect the restrictions on transfer contained in
Sections 3 and 7 of this Note. The Company may not assign its rights and
obligations hereunder without the written consent of the Holder unless the
Company enters into a merger, acquisition, sale of substantially all of the
Company's assets or similar change of control transaction.

     9. AMENDMENT AND WAIVER. The rights of the Holder may be amended or waived
upon the written consent of the Company and the Holder.

     10. INTEGRATION: NO SHAREHOLDER RIGHTS. The Agreement and this Note
constitute the full and entire understanding and agreement between the parties
hereto and thereto with regard to the subject matter hereof and thereof, and
supersede any prior or contemporaneous understandings, agreements or
representations between them that relate to the subject matter hereof or
thereof. Nothing contained in this Note shall be construed as conferring upon
the Holder or any other person the right to vote or to consent or to receive
notice as a shareholder in respect of meetings of shareholders for the election
of directors of the Company or any other matters or any rights whatsoever as a
shareholder of the Company; and no dividends or interest shall be payable or
accrued in respect of this Note or the interest represented hereby or the Shares
obtainable hereunder until, and only to the extent that, this Note shall have
been converted.

     11. CALIFORNIA LAW. This Note and the obligations of the Company and the
Holder hereunder shall be governed by and construed in accordance with the laws
of the State of California, as such laws are applied to contracts between
California residents entered into and to be performed entirely within
California.

     12. EXPENSES. The Company shall reimburse reasonable attorney fees incurred
by the Holder in connection with the enforcement of his rights under this Note.

     IN WITNESS WHEREOF, the Company has caused this Note to be executed by its
duly authorized representative on the date first above written.

                           TELEGEN CORPORATION

                           By:  /s/ FRED Y. KASHKOOLI
                              --------------------------------------------------
                                Fred Y. Kashkooli, Chief Executive Officer




<PAGE>


                              SCHEDULE OF EXHIBITS

EXHIBIT A         -   Notice of Conversion (Section 2 (a))

EXHIBIT B         -   Investment Representation Certificate (Section 2 (b))

EXHIBIT C         -   Assignment Form (Section 7)



<PAGE>

                                    EXHIBIT A

                             NOTICE OF EXERCISE FORM

                    (To be executed only upon partial or full
                        conversion of the attached Note)

         The undersigned registered Holder of the attached Note hereby
irrevocably converts $__________ in face value to Common Stock of Telegen
Corporation at the Conversion Price and on the terms and conditions specified in
the attached Note.

         The undersigned requests that a certificate (or ___________certificates
in denominations of ___________ shares) for the shares of Common Stock of
Telegen Corporation hereby received be issued in the name of and delivered to
(circle one) (a) the undersigned or (b) __________________, whose address is
____________________________________________ and, if such shares of Common Stock
shall not include all the shares of Common Stock issuable as provided in the
attached Note, that a new Note of like tenor for the number of shares of Common
Stock of Telegen Corporation not being purchased hereunder be issued in the name
of and delivered to (circle one) (a) the undersigned or (b)____________________,
whose address is _______________________________________.

Dated: _________________________, 199_






                           By:
                              --------------------------------------------------
                                (Signature of Registered Holder)

                           Title:
                                 -----------------------------------------------

NOTICE:           The signature to this Notice of Exercise must correspond with
                  the name as written upon the face of the attached Note in
                  every particular, without alteration or enlargement or any
                  change whatever.




<PAGE>


                                    EXHIBIT B

                      INVESTMENT REPRESENTATION CERTIFICATE

Purchaser:
                  --------------------------------------------------------------

Company:          Telegen Corporation, a California corporation

Security:         Common Stock

Amount:
                  --------------------------------------------------------------

Date:
                  --------------------------------------------------------------

     In connection with the purchase of the above-listed securities (the
"Securities"), the undersigned (the "Purchaser") represents to the Company as
follows:

          (a) The Purchaser is aware of the Company's business affairs and
financial condition, and has acquired sufficient information about the Company
to reach an informed and knowledgeable decision to acquire the Securities. The
Purchaser is purchasing the Securities for its own account for investment
purposes only and not with a view to, or for the resale in connection with, any
"distribution" thereof for purposes of the Securities Act of 1933, as amended
(the "Securities Act");

          (b) The Purchaser understands that the Securities may have not been
registered under the Securities Act in reliance upon a specific exemption
therefor, which exemption depends upon, among other things, the bona fide nature
of the Purchaser's investment intent as expressed herein. In this connection,
the Purchaser understands that, in the view of the Securities and Exchange
Commission (the "Commission"), the statutory basis for such exemption may be
unavailable if the Purchaser's representation was predicated solely upon a
present intention to hold these Securities for the minimum capital gains period
specified under tax statutes, for a deferred sale, for or until an increase or
decrease in the market price of the Securities, or for a period of one year or
any other fixed period in the future;

          (c) The Purchaser further understands that the Securities must be held
indefinitely unless subsequently registered under the Securities Act or unless
an exemption from registration is otherwise available. In addition, the
Purchaser understands that the certificate evidencing the Securities will be
imprinted with the legend referred to in the Warrant under which the Securities
are being purchased unless there exists an effective registration statement for
such securities;

          (d) The Purchaser is aware of the provisions of Rule 144, promulgated
under the Securities Act, which, in substance, permit limited public resale of
"restricted securities" acquired, directly or indirectly, from the issuer
thereof (or from an affiliate of such issuer), in a non-public offering subject
to the satisfaction of certain conditions, if applicable, including, among other
things: (i) the availability of certain public information about the Company;
(ii) the resale occurring not less than one (1) year after the party has
purchased and paid for the securities to be sold; (iii) the sale being made
through a broker in an unsolicited "broker's transaction" or in transactions
directly with a market maker (as said term is defined under the Securities
Exchange Act of 1934) and the amount of securities being sold during any
three-month period not exceeding the specified limitations stated therein;

          (e) The Purchaser further understands that at the time it wishes to
sell the Securities there may be no public market upon which to make such a
sale, and that, even if such a public market upon which to make such a sale then
exists, the Company may not be satisfying the current public information
requirements of Rule 144, and that, in such event, the Purchaser may be
precluded from selling the Securities under Rule 144 even if the one-year
minimum holding period had been satisfied; and

<PAGE>

          (f) The Purchaser further understands that in the event all of the
requirements of Rule 144 are not satisfied, registration under the Securities
Act, compliance with Regulation A, or some other registration exemption will be
required; and that, notwithstanding the fact that Rule 144 is not exclusive, the
staff of the Commission has expressed its opinion that persons proposing to sell
private placement securities other than in a registered offering and otherwise
than pursuant to Rule 144 will have a substantial burden of proof in
establishing that an exemption from registration is available for such offers or
sales, and that such persons and their respective brokers who participate in
such transactions do so at their own risk.

Date: ___________________, 199_


                                   PURCHASER:

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




<PAGE>

                                    EXHIBIT C

                                 ASSIGNMENT FORM

      (To be executed only upon the assignment of the attached securities)

         FOR VALUE RECEIVED, the undersigned registered Holder of the attached
securities hereby sells, assigns and transfers unto ______________, whose
address is __________________all of the rights of the undersigned under the
attached securities, with respect to ____________ shares of Common Stock of
Telegen Corporation and, if applicable, if such shares of Common Stock shall not
include all the shares of Common Stock issuable as provided in the attached Note
then a new Note of like tenor for the number of shares of Common Stock of
Telegen Corporation not being transferred hereunder be issued in the name of and
delivered to the undersigned, and does hereby irrevocably constitute and appoint
____________________ attorney to register such transfer on the books of Telegen
Corporation maintained for the purpose, with full power of substitution in the
premises.

Dated: _____________________,  199_


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

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

                         By:
                            ----------------------------------------------------
                              (Signature of Registered Holder)

                         Title:
                               -------------------------------------------------



NOTICE:           The signature to this Assignment must correspond with the name
                  upon the face of the attached certificate of Common Stock or
                  Note being surrendered herewith in every particular, without
                  alteration or enlargement or any change whatever.