Exhibits 5 and 23.1




                                 August 25, 2000



Board of Directors
APA Optics, Inc.
2950 N.E. 84th Lane
Blaine, Minnesota 55449

         Re:    Registration Statement for 185,000 Shares of Common Stock to be
                issued pursuant to APA Optics, Inc. Stock Option Plan for
                Nonemployee Directors
                Our File No.: 52226.1

Gentlemen:

         This opinion is given in connection with the filing by APA Optics, Inc.
with the Securities and Exchange Commission under the Securities Act of 1933, of
a Registration Statement on Form S-8 (the "Registration Statement"), with
respect to 185,000 shares of the Registrant's Common Stock, $.01 par value (the
"Shares"), that may be issued upon exercise of options or other awards that have
been or may be granted under the Registrant's Stock Option Plan for Nonemployee
Directors (the "Plan").

         We have acted as counsel for the Registrant in connection with the
filing of the Registration Statement. In so acting, we have examined the
originals or copies, certified or otherwise identified to our satisfaction, of
all corporate instruments and have made such inquiries of officers and
representatives of the Registrant as we have deemed relevant and necessary as a
basis for the opinion hereinafter set forth. In such examination, we have
assumed the genuineness of all signatures and the authenticity of all documents
submitted to us as originals and the conformity to the original of documents
submitted to us as certified or photostatic copies. As to questions of fact
material to such opinion that we have not independently established, we have
relied upon representations or certificates of officers and directors of the
Registrant.


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Board of Directors
August 25, 2000
Page 2


         Based upon the foregoing, we are of the following opinion:

         1.       The Registrant has been duly incorporated and is validly
                  existing as a corporation under the laws of the State of
                  Minnesota.

         2.       The Shares have been duly authorized and when issued and
                  delivered as contemplated under the Plan will be validly
                  issued and outstanding, fully paid and nonassessable.

         We consent to the use of this opinion as an exhibit to the Registration
Statement. We further consent to the use of this opinion as an exhibit to
applications to the securities commissioners of various states of the United
States for registration therein of various aggregate amounts of the Shares.

                                       Very truly yours,

                                       MOSS & BARNETT
                                       A Professional Association

                                       /s/ Deanne M. Greco

                                       Deanne M. Greco

DMG/ggb


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