8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 13, 2006

MICROSEMI CORPORATION

(Exact name of registrant as specified in its charter)

Delaware	0-8866	95-2110371
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

2381 Morse Avenue, Irvine, California	92614
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code

(949) 221-7100

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

x Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

INTRODUCTION

This Form 8-K is filed pursuant to Rules 165 and 425 promulgated under the Securities Act of 1933, as amended. Pursuant to Rule 425, the Exhibit filed herewith and incorporated by reference shall be deemed filed with, rather than furnished to, the Securities and Exchange Commission (“SEC”).

Microsemi Corporation (the “Registrant”) has filed with the SEC a registration statement on Form S-4 (Reg. No. 333-130655) on March 23, 2006, and a prospectus on March 28, 2006, for the acquisition of Advanced Power Technology, Inc., a Delaware corporation (“APT”), to which the Exhibit filed herewith relates. Before you take any action, you should read the prospectus and the registration statement and other documents the Registrant or APT has filed with the SEC. You may get these documents for free by visiting EDGAR on the SEC Web Site at www.sec.gov. Alternatively, the Registrant will arrange to send you the prospectus if you request it by calling 949-221-7101.

INFORMATION TO BE INCLUDED IN THE REPORT

Section 8 – Other Events

Item 8.01 Other Events

On April 13, 2006, Advanced Power Technology, Inc. caused to be mailed a Notice of Dissenters’ Appraisal Rights to holders of record of its Common Stock as of March 3, 2006.

A copy of the Notice from Advanced Power Technology, Inc. is attached as Exhibit 99.1 to this report and is incorporated herein by this reference.

Section 9—Financial Statements and Exhibits

Item 9.01 Financial Statements and Exhibits.

Exhibit No.	Description
99.1	Notice to Holders of APT Common Stock of Dissenters’ Appraisal Rights.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MICROSEMI CORPORATION
	(Registrant)
Date: April 13, 2006	/S/    DAVID R. SONKSEN
	David R. Sonksen Executive Vice President, Chief Financial Officer, Treasurer and Secretary

EXHIBIT INDEX

Exhibit No.	Description
99.1	Notice to Holders of APT Common Stock of Dissenters’ Appraisal Rights.

EX-99.1

EXHIBIT 99.1

Filed by Microsemi Corporation

Pursuant to Rule 425 under the Securities Act of 1933, as amended

Registration No. 333-130655

Acquiring Company: Microsemi Corporation (000-08866)

Subject Company: Advanced Power Technology, Inc. (001-16047)

A proxy statement/prospectus filed by Microsemi and APT with the Securities and Exchange Commission (the “SEC”) contains important information related to the proposed merger that you should read before making any decisions and is available to you without charge from http://www.sec.gov or upon your written or oral request to Microsemi Corporation, 2381 Morse Avenue, Irvine, California 92614, Tel: (949) 221-7100, or Advanced Power Technology, Inc., 405 S.W. Columbia Street, Bend, Oregon 97702, Tel: (541) 382-8028. This Notice of Dissenters’ Appraisal Rights supersedes all statements to the contrary in the proxy statement/prospectus (i.e., on page 4 and page 70 thereof).

ADVANCED POWER TECHNOLOGY, INC.

405 S.W. Columbia Street

Bend, Oregon 97702

NOTICE OF DISSENTERS’ APPRAISAL RIGHTS

Dear Stockholders of Advanced Power Technology, Inc.:

Stockholders of Advanced Power Technology, Inc., a Delaware corporation (“APT”) are entitled to dissenters’ appraisal rights in connection with the proposed merger (the “merger”) of APT with APT Acquisition Corp., a wholly owned subsidiary of Microsemi Corporation. Under Delaware law, dissenters who perfect their appraisal rights on the conditions described below, would receive, for each share of APT common stock, the appraised fair value of a share, instead of the merger consideration of 0.435 of a share of Microsemi common stock and $2.00 in cash. The appraised value may be less than, equal to or greater than the merger consideration provided for in the merger agreement. The value of the APT common stock for this purpose will exclude any element of value arising from the accomplishment or expectation of the merger.

The following is a summary of 8 Delaware Code § 262, which specifies the procedures applicable to dissenting stockholders. This summary is not a complete statement of the law regarding your right to dissent under Delaware law, and if you are considering dissenting, we urge you to review the provisions of § 262 carefully. The full text of § 262 is found further below. If you fail to comply with the procedural requirements of § 262 of the Delaware General Corporation Law, you will lose your right to dissent and seek payment in cash of the appraised value of your shares instead of the merger consideration.

In order to dissent and receive the appraised fair value of your shares:

• before the APT special meeting, or any adjournment or postponement thereof, the record holder* of the shares must deliver a written notice that states its identity and its intent to demand appraisal to Advanced Power Technology, Inc., 405 S.W. Columbia Street, Bend, Oregon 97702, Attention: Greg M. Haugen, Secretary (you should be aware that simply voting against the merger is not a demand for appraisal rights); and

• you must hold shares of APT common stock on the date when you make the demand required under Delaware law, and you must continuously hold those shares until the merger has been completed; and

• you must not vote in favor of the merger (including by appointing a proxy to vote your shares).

*Where shares of APT are held in the name of brokers or fiduciaries (commonly called “street name”) for your account, the brokers or fiduciaries are the stockholders of record. If the beneficial owners so desire, the beneficial owners should instruct and notify the record holders to perfect the appraisal rights as described above.

Also, among other matters, you should be aware of the following:

• within ten days after the effective time of the merger, the surviving company will notify all of the dissenting APT stockholders who have complied with § 262 and who have not voted in favor of the merger;

• within 120 days after the effective time of the merger, any stockholder who has complied with the requirements of § 262 may file a petition in the Delaware Court of Chancery demanding a determination of the value of the stock of the dissenting stockholders;

• the Delaware Court of Chancery will determine which dissenting stockholders complied with the requirements of § 262 and are entitled to appraisal rights;

• the Court of Chancery will then appraise the shares, determining their fair value exclusive of any value arising from the accomplishment or expectation of the merger, together with a fair rate of interest, if any, to be paid on the appraised fair value; the Court of Chancery will consider all relevant factors in determining the fair value and the fair interest rate (if any);

• the Court of Chancery will then direct the surviving company to pay the fair value of the dissenting shares, together with any interest, to the stockholders entitled to payment; payment will be made when the stockholder surrenders the certificates to the surviving company;

• the costs of the proceeding for appraising the fair value may be determined by the court and the court may require the parties to bear the costs in any manner that the court believes to be equitable; and

• you may withdraw your demand for appraisal and accept the merger consideration provided for in the merger agreement at any time within 60 days after the effective date of the merger.

* * *

8 Delaware Code § 262 Appraisal rights

(a) Any stockholder of a corporation of this State who holds shares of stock on the date of the making of a demand pursuant to subsection (d) of this section with respect to such shares, who continuously holds such shares through the effective date of the merger or consolidation, who has otherwise complied with subsection (d) of this section and who has neither voted in favor of the merger or consolidation nor consented thereto in writing pursuant to § 228 of this title shall be entitled to an appraisal by the Court of Chancery of the fair value of the stockholder’s shares of stock under the circumstances described in subsections (b) and (c) of this section. As used in this section, the word “stockholder” means a holder of record of stock in a stock corporation and also a member of record of a nonstock corporation; the words “stock” and “share” mean and include what is ordinarily meant by those words and also membership or membership interest of a member of a nonstock corporation; and the words “depository receipt” mean a receipt or other instrument issued by a depository representing an interest in one or more shares, or fractions thereof, solely of stock of a corporation, which stock is deposited with the depository.

(b) Appraisal rights shall be available for the shares of any class or series of stock of a constituent corporation in a merger or consolidation to be effected pursuant to § 251 (other than a merger effected pursuant to § 251(g) of this title), § 252, § 254, § 257, § 258, § 263 or § 264 of this title:

(1) Provided, however, that no appraisal rights under this section shall be available for the shares of any class or series of stock, which stock, or depository receipts in respect thereof, at the record date fixed to

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determine the stockholders entitled to receive notice of and to vote at the meeting of stockholders to act upon the agreement of merger or consolidation, were either (i) listed on a national securities exchange or designated as a national market system security on an interdealer quotation system by the National Association of Securities Dealers, Inc. or (ii) held of record by more than 2,000 holders; and further provided that no appraisal rights shall be available for any shares of stock of the constituent corporation surviving a merger if the merger did not require for its approval the vote of the stockholders of the surviving corporation as provided in subsection (f) of § 251 of this title.

(2) Notwithstanding paragraph (1) of this subsection, appraisal rights under this section shall be available for the shares of any class or series of stock of a constituent corporation if the holders thereof are required by the terms of an agreement of merger or consolidation pursuant to § § 251, 252, 254, 257, 258, 263 and 264 of this title to accept for such stock anything except:

a. Shares of stock of the corporation surviving or resulting from such merger or consolidation, or depository receipts in respect thereof;

b. Shares of stock of any other corporation, or depository receipts in respect thereof, which shares of stock (or depository receipts in respect thereof) or depository receipts at the effective date of the merger or consolidation will be either listed on a national securities exchange or designated as a national market system security on an interdealer quotation system by the National Association of Securities Dealers, Inc. or held of record by more than 2,000 holders;

c. Cash in lieu of fractional shares or fractional depository receipts described in the foregoing subparagraphs a. and b. of this paragraph; or

d. Any combination of the shares of stock, depository receipts and cash in lieu of fractional shares or fractional depository receipts described in the foregoing subparagraphs a., b. and c. of this paragraph.

(3) In the event all of the stock of a subsidiary Delaware corporation party to a merger effected under § 253 of this title is not owned by the parent corporation immediately prior to the merger, appraisal rights shall be available for the shares of the subsidiary Delaware corporation.

(c) Any corporation may provide in its certificate of incorporation that appraisal rights under this section shall be available for the shares of any class or series of its stock as a result of an amendment to its certificate of incorporation, any merger or consolidation in which the corporation is a constituent corporation or the sale of all or substantially all of the assets of the corporation. If the certificate of incorporation contains such a provision, the procedures of this section, including those set forth in subsections (d) and (e) of this section, shall apply as nearly as is practicable.

(d) Appraisal rights shall be perfected as follows:

(1) If a proposed merger or consolidation for which appraisal rights are provided under this section is to be submitted for approval at a meeting of stockholders, the corporation, not less than 20 days prior to the meeting, shall notify each of its stockholders who was such on the record date for such meeting with respect to shares for which appraisal rights are available pursuant to subsection (b) or (c) hereof that appraisal rights are available for any or all of the shares of the constituent corporations, and shall include in such notice a copy of this section. Each stockholder electing to demand the appraisal of such stockholder’s shares shall deliver to the corporation, before the taking of the vote on the merger or consolidation, a written demand for appraisal of such stockholder’s shares. Such demand will be sufficient if it reasonably informs the corporation of the identity of the stockholder and that the stockholder intends thereby to demand the appraisal of such stockholder’s shares. A proxy or vote against the merger or consolidation shall not constitute such a demand. A stockholder electing to take such action must do so by a separate written demand as herein provided. Within 10 days after the effective date of such merger or consolidation, the surviving or resulting corporation shall notify each stockholder of each constituent corporation who has

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complied with this subsection and has not voted in favor of or consented to the merger or consolidation of the date that the merger or consolidation has become effective; or

(2) If the merger or consolidation was approved pursuant to § 228 or § 253 of this title, then either a constituent corporation before the effective date of the merger or consolidation or the surviving or resulting corporation within 10 days thereafter shall notify each of the holders of any class or series of stock of such constituent corporation who are entitled to appraisal rights of the approval of the merger or consolidation and that appraisal rights are available for any or all shares of such class or series of stock of such constituent corporation, and shall include in such notice a copy of this section. Such notice may, and, if given on or after the effective date of the merger or consolidation, shall, also notify such stockholders of the effective date of the merger or consolidation. Any stockholder entitled to appraisal rights may, within 20 days after the date of mailing of such notice, demand in writing from the surviving or resulting corporation the appraisal of such holder’s shares. Such demand will be sufficient if it reasonably informs the corporation of the identity of the stockholder and that the stockholder intends thereby to demand the appraisal of such holder’s shares. If such notice did not notify stockholders of the effective date of the merger or consolidation, either (i) each such constituent corporation shall send a second notice before the effective date of the merger or consolidation notifying each of the holders of any class or series of stock of such constituent corporation that are entitled to appraisal rights of the effective date of the merger or consolidation or (ii) the surviving or resulting corporation shall send such a second notice to all such holders on or within 10 days after such effective date; provided, however, that if such second notice is sent more than 20 days following the sending of the first notice, such second notice need only be sent to each stockholder who is entitled to appraisal rights and who has demanded appraisal of such holder’s shares in accordance with this subsection. An affidavit of the secretary or assistant secretary or of the transfer agent of the corporation that is required to give either notice that such notice has been given shall, in the absence of fraud, be prima facie evidence of the facts stated therein. For purposes of determining the stockholders entitled to receive either notice, each constituent corporation may fix, in advance, a record date that shall be not more than 10 days prior to the date the notice is given, provided, that if the notice is given on or after the effective date of the merger or consolidation, the record date shall be such effective date. If no record date is fixed and the notice is given prior to the effective date, the record date shall be the close of business on the day next preceding the day on which the notice is given.

(e) Within 120 days after the effective date of the merger or consolidation, the surviving or resulting corporation or any stockholder who has complied with subsections (a) and (d) hereof and who is otherwise entitled to appraisal rights, may file a petition in the Court of Chancery demanding a determination of the value of the stock of all such stockholders. Notwithstanding the foregoing, at any time within 60 days after the effective date of the merger or consolidation, any stockholder shall have the right to withdraw such stockholder’s demand for appraisal and to accept the terms offered upon the merger or consolidation. Within 120 days after the effective date of the merger or consolidation, any stockholder who has complied with the requirements of subsections (a) and (d) hereof, upon written request, shall be entitled to receive from the corporation surviving the merger or resulting from the consolidation a statement setting forth the aggregate number of shares not voted in favor of the merger or consolidation and with respect to which demands for appraisal have been received and the aggregate number of holders of such shares. Such written statement shall be mailed to the stockholder within 10 days after such stockholder’s written request for such a statement is received by the surviving or resulting corporation or within 10 days after expiration of the period for delivery of demands for appraisal under subsection (d) hereof, whichever is later.

(f) Upon the filing of any such petition by a stockholder, service of a copy thereof shall be made upon the surviving or resulting corporation, which shall within 20 days after such service file in the office of the Register in Chancery in which the petition was filed a duly verified list containing the names and addresses of all stockholders who have demanded payment for their shares and with whom agreements as to the value of their shares have not been reached by the surviving or resulting corporation. If the petition shall be filed by the surviving or resulting corporation, the petition shall be accompanied by such a duly verified list. The Register in Chancery, if so ordered by the Court, shall give notice of the time and place fixed for the hearing

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of such petition by registered or certified mail to the surviving or resulting corporation and to the stockholders shown on the list at the addresses therein stated. Such notice shall also be given by 1 or more publications at least 1 week before the day of the hearing, in a newspaper of general circulation published in the City of Wilmington, Delaware or such publication as the Court deems advisable. The forms of the notices by mail and by publication shall be approved by the Court, and the costs thereof shall be borne by the surviving or resulting corporation.

(g) At the hearing on such petition, the Court shall determine the stockholders who have complied with this section and who have become entitled to appraisal rights. The Court may require the stockholders who have demanded an appraisal for their shares and who hold stock represented by certificates to submit their certificates of stock to the Register in Chancery for notation thereon of the pendency of the appraisal proceedings; and if any stockholder fails to comply with such direction, the Court may dismiss the proceedings as to such stockholder.

(h) After determining the stockholders entitled to an appraisal, the Court shall appraise the shares, determining their fair value exclusive of any element of value arising from the accomplishment or expectation of the merger or consolidation, together with a fair rate of interest, if any, to be paid upon the amount determined to be the fair value. In determining such fair value, the Court shall take into account all relevant factors. In determining the fair rate of interest, the Court may consider all relevant factors, including the rate of interest which the surviving or resulting corporation would have had to pay to borrow money during the pendency of the proceeding. Upon application by the surviving or resulting corporation or by any stockholder entitled to participate in the appraisal proceeding, the Court may, in its discretion, permit discovery or other pretrial proceedings and may proceed to trial upon the appraisal prior to the final determination of the stockholder entitled to an appraisal. Any stockholder whose name appears on the list filed by the surviving or resulting corporation pursuant to subsection (f) of this section and who has submitted such stockholder’s certificates of stock to the Register in Chancery, if such is required, may participate fully in all proceedings until it is finally determined that such stockholder is not entitled to appraisal rights under this section.

(i) The Court shall direct the payment of the fair value of the shares, together with interest, if any, by the surviving or resulting corporation to the stockholders entitled thereto. Interest may be simple or compound, as the Court may direct. Payment shall be so made to each such stockholder, in the case of holders of uncertificated stock forthwith, and the case of holders of shares represented by certificates upon the surrender to the corporation of the certificates representing such stock. The Court’s decree may be enforced as other decrees in the Court of Chancery may be enforced, whether such surviving or resulting corporation be a corporation of this State or of any state.

(j) The costs of the proceeding may be determined by the Court and taxed upon the parties as the Court deems equitable in the circumstances. Upon application of a stockholder, the Court may order all or a portion of the expenses incurred by any stockholder in connection with the appraisal proceeding, including, without limitation, reasonable attorney’s fees and the fees and expenses of experts, to be charged pro rata against the value of all the shares entitled to an appraisal.

(k) From and after the effective date of the merger or consolidation, no stockholder who has demanded appraisal rights as provided in subsection (d) of this section shall be entitled to vote such stock for any purpose or to receive payment of dividends or other distributions on the stock (except dividends or other distributions payable to stockholders of record at a date which is prior to the effective date of the merger or consolidation); provided, however, that if no petition for an appraisal shall be filed within the time provided in subsection (e) of this section, or if such stockholder shall deliver to the surviving or resulting corporation a written withdrawal of such stockholder’s demand for an appraisal and an acceptance of the merger or consolidation, either within 60 days after the effective date of the merger or consolidation as provided in subsection (e) of this section or thereafter with the written approval of the corporation, then the right of such stockholder to an appraisal shall cease. Notwithstanding the foregoing, no appraisal proceeding in the Court of Chancery shall be dismissed as to any stockholder without the approval of the Court, and such approval may be conditioned upon such terms as the Court deems just.

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(l) The shares of the surviving or resulting corporation to which the shares of such objecting stockholders would have been converted had they assented to the merger or consolidation shall have the status of authorized and unissued shares of the surviving or resulting corporation.

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The proxy statement/prospectus filed by Microsemi and APT with the Securities and Exchange Commission (the “SEC”) contains important information that you should read before making a decision and is available to you without charge from www.sec.gov or upon your written or oral request to: Advanced Power Technology, Inc., 405 S.W. Columbia Street, Bend, Oregon 97702, Tel: (541) 382-8028. This Notice of Dissenters’ Appraisal Rights supersedes all statements to the contrary in the proxy statement/prospectus related to the merger (i.e., on page 4 and page 70 thereof).

By order of the Board of Directors,

Greg M. Haugen

Vice President, Finance and Administration,

Chief Financial Officer and Secretary

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