Filer: Thermo Electron Corporation
                                                Subject Company: Thermedics Inc.
                                   Subject Company Exchange Act File No.: 1-9567
                                           Registration Statement No.: 333-35982

PRESS RELEASE
Investor Contact: 781-622-1111
Media Contact: 781-622-1252


                   Thermo Electron Extends Exchange Offer for
                        Thermedics Shares to June 9, 2000

WALTHAM,  Mass., May 30, 2000 - Thermo Electron Corporation (NYSE-TMO) announced
that it has extended the offer for Thermedics Inc.  (ASE-TMD) common stock until
midnight on June 9, 2000. This extension is required  because the Securities and
Exchange  Commission (SEC) has not yet completed its review of Thermo Electron's
registration statement for the exchange offer. The company may not accept shares
of Thermedics common stock tendered in the exchange offer until the registration
statement is declared  effective by the SEC.  Other terms and  conditions of the
exchange offer remain unchanged.

According to a preliminary  report from the depositary  for the exchange  offer,
approximately  7.7 million  shares of Thermedics  common stock had been tendered
and not withdrawn  pursuant to the exchange offer as of the close of business on
Friday,  May 26, 2000. These shares represent  approximately 18 percent of total
Thermedics  shares  outstanding,  and when  combined  with shares held by Thermo
Electron, represent approximately 94 percent.

Because of the extension announced today, holders of Thermedics common stock may
tender or withdraw their shares until midnight on Friday,  June 9, 2000,  unless
the exchange offer is further  extended.  The exchange offer previously had been
scheduled to expire at midnight on May 26, 2000.

 On May 1, 2000,  Thermo Electron mailed a preliminary  prospectus to registered
holders of  Thermedics  shares  regarding  the  exchange  offer and the  merger,
accompanied by a letter of transmittal  that Thermedics  shareholders can use to
tender their  shares in the  exchange  offer.  Beneficial  owners of  Thermedics
shares holding in street name through their brokers can receive the  preliminary
prospectus and letter of transmittal  from their broker and should contact their
brokers for those documents.  In any case, copies of the preliminary  prospectus
and letter of  transmittal  may be requested  from D.F.  King & Co.,  Inc.,  the
information agent for the exchange offer, by calling (800) 290-6433.

Thermo Electron  Corporation is a leading  provider of analytical and monitoring
instruments used in a broad range of applications,  from life sciences  research
to  telecommunications  to food and beverage  production.  In  addition,  Thermo
Electron serves the healthcare market through a family of medical products,  and
is a major producer of paper recycling systems and provides  water-clarification
and fiber-recovery  products and services. As announced on January 31, 2000, the
company has initiated a major  reorganization  that would  transform it into one
company focused on its core measurement and detection instruments business. More
information is available on the Internet at http://www.thermo.com.

                                     -more-


Other Important Information:

We urge investors and security holders to read the following documents when they
become available,  regarding the exchange offer and the merger described in this
announcement, because they contain important information:

Thermo  Electron's  preliminary  prospectus,  any prospectus  supplement,  final
prospectus, and other exchange offer materials.

Thermo  Electron's  registration  statement  on form  S-4 and  Schedule  TO,  as
amended,  which contain or incorporate  by reference the documents  listed above
and other information.

Thermedics' solicitation/recommendation statement on schedule 14D-9.

These  documents and  amendments to these  documents  have been or will be filed
with the SEC. When these and other documents are filed with the SEC, they may be
obtained for free at the SEC's Web site at www.sec.gov.  You may also obtain for
free each of these documents,  when available, from us. You can call us at (781)
622-1111 or write to us at:

Investor Relations Department
Thermo Electron Corporation
81 Wyman Street, P.O. Box 9046
Waltham, MA  02454-9046

The following constitutes a "Safe Harbor" statement under the Private Securities
Litigation  Reform Act of 1995:  This  press  release  contains  forward-looking
statements that involve a number of risks and  uncertainties.  Important factors
that could cause actual  results to differ  materially  from those  indicated by
such forward-looking statements are set forth under the heading "Forward-Looking
Statements"  in Exhibit 13 to the company's  annual report on Form 10-K, for the
year ended January 1, 2000. These include risks and  uncertainties  relating to:
the company's corporate  reorganization,  acquisition strategy, growth strategy,
international operations, product development and technological change, possible
changes  in  governmental  regulations,  changes  in both  capital  spending  by
commercial  customers  and  government  funding  policies,   and  dependence  on
intellectual property rights.


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