10. Income Taxes: (Tables)

12 Months Ended

May 31, 2022

Income Tax Disclosure [Abstract]

Income Taxes Table

	2022		2021
Current tax provision (benefit):
Federal	$	200,100	$	(361,000	)
State		1,400		—
		201,500		(361,000	)
Deferred tax provision (benefit):
Federal		115,500		(20,000	)
State		—		—
		115,500		(20,000	)
	$	317,000	$	(381,000	)

Reconciliation of income tax statutory rate to effective rate

	2022			2021
Computed tax provision at the expected statutory rate	$	536,800		$	143,200
State income tax - net of Federal tax benefit		1,100			—
Tax effect of permanent differences:
Research tax credits		(275,400	)		(218,000	)
Foreign-derived intangible income deduction		(12,200	)		—
PPP loan forgiveness		—			(306,900	)
Other permanent differences		3,100			41,500
Other		63,600			(40,800	)
Total tax provision	$	317,000		$	(381,000	)
Effective income tax rate		12.4	%		(55.9	%)

Components of Deferred Tax Assets and Liabilities

	2022			2021
Deferred tax assets:
Allowance for doubtful receivables	$	3,400		$	1,400
Tax inventory adjustment		92,200			22,900
Allowance for obsolete inventory		278,800			440,800
Accrued vacation		84,300			81,400
Accrued commissions		7,000			5,900
Warranty reserve		48,800			23,900
R&D tax credit		84,000			—
Stock options issued for services		277,600			238,500
Total deferred tax assets		876,100			814,800
Deferred tax liabilities:
Excess tax depreciation		(801,485	)		(624,685	)
Net deferred tax assets	$	74,615		$	190,115