UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13D

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934
                             (AMENDMENT NO. ______)*


                       ELECTRONIC SENSOR TECHNOLOGY, INC.
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                                (Name of Issuer)

                                  Common Stock
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                              (Title of Securities)

                                   285835 10 4
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                                 (CUSIP Number)

                       ELECTRONIC SENSOR TECHNOLOGY, INC.
                           1077 Business Center Circle
                             Newbury Park, CA 91320
                                 (805) 480-1994
                            Attention: Francis Chang
          (Names, Address and Telephone Number of Person Authorized to
                      Receive Notices and Communications)

                                February 1, 2005
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             (Date of Event Which Requires Filing of This Statement)

If the filing person has previously  filed a statement on Schedule 13G to report
the  acquisition  that is the subject of this  Schedule  13D, and is filing this
schedule  because of Rule 13d-1(e),  Rule 12d-1(f) or Rule  13d-1(g),  check the
following box. [ ]

Note:  Schedules  filed in paper format shall include a signed original and five
copies of the  schedule,  including  all  exhibits.  See Rule 13d-7(b) for other
parties to whom copies are to be sent.

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for  any  subsequent   amendment   containing   information  which  would  alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).



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CUSIP No.                                                      Page 1 of 4 Pages
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1     Names of Reporting Persons
      IRS Identification Nos. of Above Persons

      FRANCIS CHANG

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2     Check the Appropriate Box if a Member of a Group (See Instructions)

      (a)   |_| Not Applicable
      (b)   |_| Not Applicable

      Not Applicable

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3     SEC Use Only

4     Source of Funds SC

5     Check if Disclosure  of Legal  Proceedings  is Required  Pursuant to Items
      2(d) or 2(e)

      Not Applicable
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6     Citizenship or Place of Organization      California
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Number of Shares Beneficially Owned by Each Reporting Person With:

7     Sole Voting Power   3,933,160

8     Shared Voting Power   Not Applicable

9     Sole Dispositive Power   3,933,160

10    Shared Dispositive Power   Not Applicable
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11    Aggregate Amount Beneficially Owned by Each Reporting Person    3,933,160

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12    Check if the  Aggregate  Amount in Row (11) Excludes  Certain  Shares (See
      Instructions) |_|

      Not Applicable

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13    Percent of Class Represented by Amount in Row (9)     7.2%

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14    Type of Reporting Person (See Instructions) IN

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ITEM 1. SECURITY AND ISSUER.

This statement relates to the common stock ("Common Stock") of Electronic Sensor
Technology,  Inc., a Nevada corporation (the "Issuer").  The principal executive
offices of  Electronic  Sensor  Technology,  Inc.  are located at 1077  Business
Center Circle, Newbury Park, California 91320.

ITEM 2. IDENTITY AND BACKGROUND.

The identity of the person filing this statement is as follows:

a.    Name: Francis Chang an individual

b.    Business  Address:  1077 Business  Center Circle Newbury Park,  California
      91320

c.    Occupation:  Mr. Chang is a Director and the Vice  President,  Finance and
      Administration of the Issuer

d.    Mr.  Chang  has not,  during  the last five  years,  been  convicted  in a
      criminal    proceeding    (excluding   traffic   violations   or   similar
      misdemeanors).

e.    Mr.  Chang  was  not,  during  the  last  five  years,  a party to a civil
      proceeding of a judicial or administrative body of competent  jurisdiction
      that  resulted  in a  judgment,  decree or final  order  enjoining  future
      violations of, or prohibiting or mandating  activities subject to, federal
      or state  securities  laws or finding any  violation  with respect to such
      laws.

f.    Mr. Chang is a citizen of the United States.

ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

On February 1, 2005, Francis Chang,  through his wholly-owned  limited liability
company, 3 Springs, LLC (both Mr. Chang and 3 Springs, LLC shall be collectively
referred to as "Chang") was issued shares of common stock ("Common  Stock") from
Issuer,  and warrants to purchase  shares of Common Stock in connection with the
mergers ("Mergers") of two wholly-owned subsidiaries of Issuer with and into L &
G Sensor  Technology,  Inc.  and  Amerasia  Technology,  Inc.  such that Issuer.
indirectly  held  all  limited   partnership   interests  of  Electronic  Sensor
Technology,  L.P., a California  limited  partnership  ("EST LP"). In connection
with the Mergers,  Chang converted  666,634 shares of Amerasia common stock into
3,081,420  shares of Issuer  common  stock.  In addition,  Chang also  converted
$226,720 in principal and accrued  interests  from EST LP promissory  notes into
226,720 shares of Issuer common stock and warrants to purchase 113,360 shares of
Issuer common stock  exerciseable  at $1.00 per share.  The warrants may only be
exercised if the stock price is above $1.50 per share  ("Warrants").  Chang also
received  287,773 shares of Common Stock and 143,887 Warrants in connection with
Amerasia's  conversion of EST LP promissory notes into Issuer equity securities.
All  3,595,913  shares of Common  Stock and 257,247  Warrants are held through 3
Springs LLC, a California  limited liability company  wholly-owned by Mr. Chang.
Mr.  Chang  holds in his own name  options to purchase  80,000  shares of Common
Stock at $1.00 per share.



ITEM 4. PURPOSE OF TRANSACTION.

Chang did not  acquired  the Issuer  common  stock for the purpose of  acquiring
control of Issuer.  Except as  discussed  in this Item 4, as of the filing date,
Chang has no plans or  proposals  that related to or that would result in any of
the  actions  specified  in clauses  (b) though (j) of Item 4 of  Schedule  13D,
although it may, in the future,  in connection with its review of its investment
in the  Common  Stock  from  time to time  explore a  variety  of  alternatives,
including without limitation the aforementioned  actions.  There is no assurance
that  Chang  will  develop  any plans or  proposals  with  respect to any of the
foregoing  actions.  Any  alternatives  which best may pursue will depend upon a
variety of factors,  including,  without  limitation,  current  and  anticipated
future trading prices for the Common Stock, the financial condition,  results of
operations and prospects of Issuer and general  economic,  financial  market and
industry conditions.

ITEM 5. INTEREST IN SECURITIES OF THE ISSUER.

Pursuant to Rule 13d-3  promulgated  under the Securities  Exchange Act of 1934,
Chang is  considered  the  beneficial  owner of a total of  3,933,160  shares of
Issuer's  Common  Stock,  representing  approximately  7.2%  of all  issued  and
outstanding  shares of Common Stock.  Chang has sole voting power and sole power
to dispose of the Common Stock. Other than the Mergers, Chang has not engaged in
any transactions involving Issuer Common Stock during the past 60 days. No other
person is known to have the right to receive or the power to direct the  receipt
of dividends  from,  or the proceeds from the sale of, the Common Stock owned by
Chang.

ITEM 6. CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO
        SECURITIES OF THE ISSUER.

Not Applicable.

ITEM 7. MATERIAL TO BE FILED AS EXHIBITS.

Not Applicable.



                                    SIGNATURE

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

                                       February 23, 2005




                                       /s/ Francis Chang
                                       -----------------------------------------
                                       Francis Chang