Prentice hall's federal taxation test bank chapter 11

Prentice Hall's Federal Taxation 2013 Corporations, 26e (Pope)

Chapter C11 S Corporations

1) The S corporation rules were enacted to allow small corporations to enjoy the nontax advantages of the corporate form of business without being subject to the tax disadvantage of double taxation.

Answer: TRUE

Page Ref.: C:11-2

Objective: 1

2) Up to six generations of a family are considered as one shareholder for purposes of the 100-shareholder limit.

Answer: TRUE

Page Ref.: C:11-4

Objective: 2

3) Corporations and partnerships can be S corporation shareholders.

Answer: FALSE

Page Ref.: C:11-4,

Objective: 2

4) A testamentary trust can be an S shareholder for two years, beginning on the date the stock transfers to the trust.

Answer: TRUE

Page Ref.: C:11-5

Objective: 2

5) The election of Subchapter S status by a corporation is valid only if all shareholders consent to the election.

Answer: TRUE

Page Ref.: C:11-8

Objective: 3

6) A corporation must make an S election for the current year after March 15 in the case of a calendar-year corporation.

Answer: FALSE

Page Ref.: C:11-8

Objective: 3

7) All shareholders must consent to the revocation of S status.

Answer: FALSE

Page Ref.: C:11-9

Objective: 3

8) Even if the termination of an S election is considered to be inadvertent, the election to terminate is irrevocable.

Answer: FALSE

Page Ref.: C:11-11

Objective: 3

9) Tax-exempt interest earned by an S corporation is not reported to its shareholders because it is excluded from the shareholders' gross income.

Answer: FALSE

Page Ref.: C:11-15

Objective: 4

10) S shareholders are allocated shares of income, gain, loss, deduction, and credit based on their number of shares of stock and period of time for which the stock is held.

Answer: TRUE

Page Ref.: C:11-19

Objective: 5

11) S shareholders cannot increase the basis of their stock by a ratable share of the general S corporation liabilities.

Answer: TRUE

Page Ref.: C:11-21

Objective: 5

12) The accumulated adjustments account is the cumulative total of ordinary income or loss and separately stated items (excluding tax-exempt income and expenses) for the most recent continuous period during which the corporation has been an S corporation.

Answer: TRUE

Page Ref.: C:11-29

Objective: 7

13) Identify which of the following statements is true.

A) The S corporation rules were enacted to allow small corporations to enjoy the nontax advantages of the corporate form of business without being subject to the tax disadvantage of double taxation.

B) A partnership can elect to be taxed as a corporation under the check-the-box regulations. As a corporation, an S election can be made.

C) For C corporations that desire to be taxed like a partnership, the S corporation rules provide a practical alternative for an existing C corporation to obtain many of the tax benefits of being taxed as a partnership.

D) All of the above are true.

Answer: D

Page Ref.: C:11-2

Objective: 1

14) Which of the following corporate tax levies are imposed on an S corporation?

A) corporate income tax

B) corporate alternative minimum tax

C) accumulated earnings tax

D) None of these taxes are imposed on an S corporation.

Answer: D

Page Ref.: C:11-3

Objective: 1

15) Identify which of the following statements is true.

A) A partnership can be an S corporation shareholder.

B) A nonresident alien can be an S corporation shareholder.

C) An S corporation can have more than 100 shareholders, since families are treated as a single shareholder.

D) All of the above are false.

Answer: C

Page Ref.: C:11-4

Objective: 2

16) Which one of the following individuals or entities is ineligible to be an S corporation shareholder?

A) an estate

B) resident alien of the United States

C) a voting trust where all of the beneficiaries are U.S. citizens

D) a partnership where all of the partners are U.S. citizens

Answer: D

Page Ref.: C:11-4

Objective: 2

17) Which of the following statements about stock ownership is not correct?

A) A C corporation can own stock of an S corporation.

B) An S corporation can own stock of a C corporation.

C) A tax-exempt charity can own stock of an S corporation.

D) An S corporation can own stock of a Qualified Subchapter S Subsidiary.

Answer: A

Page Ref.: C:11-4

Objective: 2

18) Trusts that can own S corporation stock include all of the following except

A) charitable remainder unitrusts.

B) QSSTs.

C) grantor trusts.

D) testamentary trusts.

Answer: A

Page Ref.: C:11-5

Objective: 2

19) Which of the following would terminate a Subchapter S election?

A) Estate becomes a shareholder.

B) Grantor trust becomes a shareholder.

C) Voting trust becomes a shareholder.

D) Partnership becomes a shareholder.

Answer: D

Page Ref.: C:11-4 and C:11-5

Objective: 2

20) Which one of the following is not one of the corporation-related requirements for S corporation status?

A) The corporation must be a domestic corporation.

B) The corporation must not have any foreign-sourced income.

C) The corporation must not be an "ineligible" corporation.

D) The corporation must have only one class of stock.

Answer: B

Page Ref.: C:11-6

Objective: 2

21) Identify which of the following statements is true.

A) A trust can own S corporation stock and have a C corporation as a beneficiary as long as the corporation is the sole beneficiary.

B) A QSST is an arrangement whereby the stock owned by a number of shareholders is placed under

trust control for purposes of exercising the stock voting rights.

C) A testamentary trust can be converted into a QSST trust.

D) All of the above are false.

Answer: C

Page Ref.: C:11-5

Objective: 2

22) Mary, a U.S. citizen, owned 25% of the stock of Floran Corporation, an electing S corporation. At the time of her death, the Floran stock may go to all the following without affecting the S election except

A) her estate.

B) a testamentary trust.

C) a small business trust.

D) a charitable remainder unitrust.

Answer: D

Page Ref.: C:11-5

Objective: 2

23) Alligood Corporation has two classes of common stock outstanding. The Class A and Class B common stock give the shareholders identical rights and interests in the profits and assets of the corporation. Class A stock has one vote per share. Class B stock is nonvoting. Alligood Corporation may

A) not make the S election due to different voting rights.

B) make the S election once the Class B is retired.

C) make the S election at any time.

D) not make the S election due to two classes of stock.

Answer: C

Page Ref.: C:11-6; Example C:11-2

Objective: 2

24) Identify which of the following statements is true.

A) An S corporation cannot own any stock of another corporation.

B) An S corporation cannot own 100% of the stock of another S corporation.

C) An S corporation that owns all of the stock of a Qualified Subchapter S Subsidiary (QSub) must report all the income, deductions, and losses of the subsidiary on its own tax return.

D) All of the above are true.

Answer: C

Page Ref.: C:11-6

Objective: 2

25) Identify which of the following statements is true.

A) Convertible debt issues might be considered "stock" for purposes of the S corporation single class of stock requirement.

B) The S election must be made no later than the fifteenth day of the fourth month of the tax year for which the election is to be effective.

C) A majority of shareholders must consent to the S corporation election.

D) All of the above are false.

Answer: A

Page Ref.: C:11-7

Objective: 2

26) Identify which of the following statements is true.

A) Shareholders who acquire stock in an S corporation after the election date and prior to the election's effective date must consent to the election.

B) S corporation consent by shareholders is binding on the current tax year and all future tax years.

C) Only shareholders who own stock on the date an S election takes effect must consent to the election.

D) All of the above are false.

Answer: B

Page Ref.: C:11-8

Objective: 3

27) A C corporation was formed five years ago and is a fiscal-year taxpayer with a June 30 year-end. The

C corporation wants to make an S election for its tax year beginning in the current year. The election must be made by ________ (assuming permission can be obtained to continue using the fiscal year from the IRS).

A) June 30 of the current year

B) September 15 of the current year

C) June 30 of the next year

D) September 15 of the next year

Answer: B

Page Ref.: C:11-8; Example C:11-3

Objective: 3

28) Helmut and Sergei own all the stock of Zappo Corporation, a calendar-year domestic corporation. On January 30 of the current year, Sergei sells his entire interest in the Zappo stock to Nils. All three individuals are U.S. citizens. Can an S election be made for the current year?

A) not for the current year but for the next year

B) Yes, if Helmut and Nils agree to report all of the corporation's income for the entire year

C) Yes, if Sergei will also join in the election with Helmut and Nils

D) Yes, if Helmut and Nils agree to file a short-period return and Sergei also agrees to the return Answer: C

Page Ref.: C:11-8

Objective: 3

29) Davies Corporation is a calendar-year taxpayer that is owned equally by Vivian, Rob, Danny, and Doug Davies. At the close of business on May 31, Rob Davies sells his 25% stock interest to Paula Bryan. Which of the following statements about the S election is correct?

A) Paula must consent to the S election, otherwise the election terminates at the close of business on May

31.

B) A new S election form must be filed by June 30 of the same year, with all shareholders consenting to the election. If a new S election is not filed, the election terminates on June 30 of that year.

C) Paula has 30 days to terminate the S election, otherwise the election remains in place for the entire year and all subsequent years.

D) None of the above statements are correct.

Answer: D

Page Ref.: C:11-8

Objective: 3

30) The passive income test relating to an S corporation election is applied

A) daily.

B) monthly.

C) quarterly.

D) annually.

Answer: D

Page Ref.: C:11-10

Objective: 3

31) Identify which of the following statements is true.

A) All of the shareholders of an S corporation must consent to a revocation of the S election.

B) A revocation of an S corporation election can be retrospective to any date.

C) An S election will not be terminated due to excess passive income if the corporation does not have Subchapter C E&P.

D) All of the above are true.

Answer: C

Page Ref.: C:11-10

Objective: 3

32) Which of the following conditions will not cause an S election to be terminated?

A) exceeding the 100-shareholder limit

B) creating a second class of stock having a dividend preference

C) selecting an improper tax year

D) failing to file a timely tax return

Answer: D

Page Ref.: C:11-10

Objective: 3

33) On June 30 of the current year, the S election of Great Corporation is terminated, thus creating a six-month S short year and a six-month C short year. Great Corporation is a calendar-year taxpayer. The S short-year return is due

A) September 15.

B) December 15.

C) March 15 of the next year.

D) June 30 of the next year.

Answer: C

Page Ref.: C:11-11

Objective: 3

34) Krause Corporation makes an S election, believing that it has no current or accumulated E&P. However, after an IRS audit, Krause is found to have failed the passive investment income test for three consecutive years and also to have a Subchapter C E&P balance from its three pre-election tax years. The IRS will

A) automatically terminate the election and Krause cannot reelect for a 5-year time period.

B) retroactively revoke the election to the first day on which it was effective and Krause will not be able to reelect.

C) treat the error as such and allow the election to continue unbroken.

D) likely treat the termination as inadvertent and will probably approve a continued S election if the corporation distributes the Subchapter C E&P.

Answer: D

Page Ref.: C:11-11; Example C:11-8

Objective: 3

35) If an S corporation inadvertently terminates its election, the IRS

A) may permit the corporation to report as an S corporation even for the period that includes the termination date.

B) will not permit the corporation to restore its S election until the completion of a five-year waiting period.

C) will permit restoration of the S election only if the event causing the termination was not within the control of the corporation.

D) will permit restoration of the S election if a majority of the shareholders consent to the reinstatement. Answer: A

Page Ref.: C:11-11

Objective: 3

36) Identify which of the following statements is false.

A) A C corporation short-year income tax liability must be determined on an annualized basis.

B) If the termination of an S election is considered to be inadvertent, then the election is permitted to continue in place as if the termination had never occurred.

C) If an S election is terminated and the termination is not considered to be inadvertent, a ten-tax-year waiting period is required before making a new election.

D) A corporation can obtain relief for a late S election if the IRS consents.

Answer: C

Page Ref.: C:11-12

Objective: 3

37) April Corporation's Subchapter S election was voluntarily terminated for 2010. The first year that April would be eligible to reelect S corporation status is

A) 2012.

B) 2013.

C) 2014.

D) 2015.

Answer: D

Page Ref.: C:11-12

Objective: 3

38) Identify which of the following statements is true.

A) An S corporation should have a buy-sell agreement to guard itself against an ill-advised sale of its stock.

B) The terms "small business corporation" and "S corporation" are synonymous.

C) A regular corporation has common and preferred stock outstanding on January 1. On January 2, the preferred stock is canceled in a recapitalization, leaving only common stock outstanding. The corporation can make an S election for this tax year.

D) All of the above are false.

Answer: A

Page Ref.: C:11-12

Objective: 3

39) Identify which of the following statements is true.

A) The natural business year for fiscal-year election purposes is any tax year that ends within six months after the peak period of business.

B) Section 444 permits an S corporation to elect to use a fiscal year other than a permitted year.

C) A new corporation that is 100% owned by Johnny Blake, a cash method of accounting taxpayer, makes an S election for its initial tax year. The S corporation must also elect to use the cash method of accounting as its overall accounting method.

D) All of the above are false.

Answer: B

Page Ref.: C:11-13

Objective: 3

40) For an S corporation to elect to use a fiscal year other than a permitted year, the fiscal year elected must have a maximum deferral period of

A) one month.

B) two months.

C) three months.

D) six months.

Answer: C

Page Ref.: C:11-13

Objective: 3

41) When a Sec. 444 fiscal-year election is made, the S corporation makes required payments to the IRS in order to continue to use the fiscal year as its tax year. Which of the following statements about the tax year is correct?

A) The Sec. 444 payment is deductible by the S corporation as an income tax.

B) The Sec. 444 payment is allocated ratably to each shareholder and claimed as a tax payment on their own tax return(s).

C) The Sec. 444 payments are refundable if the S election is terminated.

D) The Sec. 444 payments must be made quarterly on the same dates that the S corporation's estimated tax payments are otherwise due.

Answer: C

Page Ref.: C:11-14

Objective: 3

42) An S corporation is permitted to claim

A) the dividends-received deduction.

B) a personal exemption.

C) a deduction based on the amortization of organizational expenditures.

D) a net operating loss.

Answer: C

Page Ref.: C:11-15

Objective: 4

43) Which of the following items is not separately stated for an S corporation?

A) short-term capital gain

B) dividend income

C) Section 1245 income

D) charitable contribution

Answer: C

Page Ref.: C:11-15

Objective: 4

44) Identify which of the following statements is true.

A) An election for an S corporation to use the Sec. 179 expensing election is made by the corporation and not by its shareholders.

B) The S corporation's separately stated items are in general the same ones that apply in partnership taxation.

C) An S corporation cannot claim a dividends-received deduction.

D) All of the above are true.

Answer: D

Page Ref.: C:11-15

Objective: 4

45) Identify which of the following statements is true.

A) Perry Corporation, an S corporation, receives $10,000 of dividends from a 25%-owned domestic corporation. Perry is allowed an 80% dividends-received deduction with respect to the distribution. B) An NOL is incurred by a C corporation in the current tax year. The C corporation makes an S election for the following tax year. The entire C corporation NOL carryover can be passed through to the S corporation's shareholders at the end of the following tax year.

C) Tax-exempt interest earned by an S corporation is not reported to its shareholders because it is excluded from the shareholders' gross income.

D) All of the above are false.

Answer: D

Page Ref.: C:11-15

Objective: 4

46) Identify which of the following statements is true.

A) Beach Corporation, an S corporation, has gross receipts of $240,000; taxable income of $120,000; passive investment income of $100,000; and expenses directly attributable to the passive investment income of $20,000. The corporation's excess net passive income is $32,000.

B) The built-in gains tax applicable to S corporations can be avoided if the property is held for ten years.

C) An S corporation generally will not owe the built-in gains tax if the corporation has never been a C corporation.

D) All of the above are true.

Answer: D

Page Ref.: C:11-16 and C:11-17

Objective: 4

47) Shanghai Corporation was organized and elected S status in the current year. How much passive investment income can Shanghai earn and retain its S status?

A) none

B) 80% of gross receipts

C) 50% of gross receipts

D) no limit

Answer: D

Page Ref.: C:11-16

Objective: 4

48) The recognition period for the built-in gains tax extends for how many years after the S election takes effect?

A) one year

B) three years

C) five years

D) ten years

Answer: D

Page Ref.: C:11-17

Objective: 4

49) King Corporation, a cash method taxpayer that uses the calendar year as its tax year, was incorporated on June 1, 1984. The corporation made its initial S election on December 1 of last year, effective for the current tax year. Earnings and profits of $60,000 have been retained from C corporation tax years. Which one of the following events results in the recognition of a built-in gain?

A) collection of accounts receivable in the current year that resulted from services performed last year

B) collection of interest income earned in the current year on bonds purchased on January 1 of last year

C) collection of dividends declared on April 5 of the current year on stock purchased on February 14 of the current year

D) None of the above are built-in gains.

Answer: A

Page Ref.: C:11-16 and C:11-17

Objective: 4

50) Identify which of the following statements is true.

A) Long-term capital gains may be subject to double taxation if the gains are subject to both the excess net passive income tax rules and the built-in gains tax rules.

B) Special allocations of ordinary income or loss and separately stated items that are available for partnerships are also permitted with S corporations.

C) When an S corporation's shares are sold by a shareholder during a tax year, the transferee's share of the earnings is reported from the day after the transfer date through the end of the tax year.

D) All of the above are false.

Answer: C

Page Ref.: C:11-19

Objective: 5

51) Train Corporation is an S corporation that is owned equally by Carlos and Diane at the beginning of the year. On April 21 (the 111th day of Train's tax year) of the current year, Carlos sells all of his Train Corporation stock to Andre. How many days will be used when computing Carlos's share of S corporation income for this year (a non-leap year), assuming that a special income allocation election is not made?

A) 110

B) 111

C) 254

D) 255

Answer: B

Page Ref.: C:11-19

Objective: 5

52) Cactus Corporation, an S Corporation, had accumulated earnings and profits of $100,000 at the beginning of 2008. Tex and Shirley each own 50% of the stock. Cactus does not make any distributions during 2008, but had $200,000 of ordinary income. In 2009, ordinary income was $100,000 and distributions were $100,000. What is Tex's ordinary income for 2008?

A) $0

B) $50,000

C) $100,000

D) $200,000

Answer: C

Page Ref.: C:11-19 and C:11-20

Objective: 5

53) Cactus Corporation, an S Corporation, had accumulated earnings and profits of $100,000 at the beginning of 2011. Tex and Shirley each own 50% of the stock. Cactus does not make any distributions during 2011, but had $200,000 of ordinary income. In 2012, ordinary income was $100,000 and distributions were $100,000. What is Tex's ordinary income for 2012?

A) $0

B) $50,000

C) $100,000

D) $200,000

Answer: B

Page Ref.: C:11-19 and C:11-20

Objective: 5

54) Cactus Corporation, an S Corporation, had accumulated earnings and profits of $100,000 at the beginning of 2009. Tex and Shirley each own 50% of the stock and have a basis in their stock of $50,000 on January 1, 2009. Cactus does not make any distributions during 2009, but had $200,000 of ordinary income. In 2010, ordinary income was $100,000 and distributions were $100,000. What is Tex's basis at January 1, 2011?

A) $100,000

B) $150,000

C) $200,000

D) $250,000

Answer: B

Page Ref.: C:11-19 and C:11-20

Objective: 5

55) Identify which of the following statements is true.

A) The overall S corporation loss limitation equals the shareholder's adjusted basis for his/her S corporation stock plus his/her ratable share of all S corporation liabilities.

B) The loss pass-throughs from an S corporation may produce a net operating loss for the shareholder.

C) An S corporation shareholder can increase the adjusted basis of his/her stock by any indebtedness owed the shareholder by the S corporation.

D) All of the above are false.

Answer: B

Page Ref.: C:11-20

Objective: 5

56) An electing S corporation has a $30,000 ordinary loss for the nonleap year. On January 1, Beverly and Sonya own equally all of the S corporation stock. On the 146th day of the year, Beverly gives her one-half of the S corporation stock to her daughter Becky. How much of the $30,000 ordinary loss is allocated to Beverly?

A) $25,000

B) $15,000

C) $6,000

D) $5,959

Answer: C

Explanation: C) $30,000 × 0.50 × (146/365) = $6,000

Page Ref.: C:11-20; Example C:11-17

Objective: 5

57) An electing S corporation has a $30,000 ordinary loss for the non-leap year. On January 1, Beverly and Sonya own equally all of the S corporation stock. On the 146th day of the year, Beverly gives her one-half of the S corporation stock to her daughter Becky. How much of the $30,000 ordinary loss is allocated to Sonya?

A) $25,000

B) $15,000

C) $10,000

D) $6,000

Answer: B

Explanation: B) $30,000 × 0.50 = $15,000

Page Ref.: C:11-21

Objective: 5

58) Which one of the following special loss limitations apply to an S corporation?

A) at-risk rules

B) passive activity limitation rules

C) hobby loss rules

D) All of the above apply.

Answer: D

Page Ref.: C:11-22

Objective: 5

59) Dilley Corporation is an electing S corporation that uses a calendar year as its tax year. On October 31, Dilley's S election is terminated because of the acquisition of stock by an ineligible stockholder. Dilley Corporation shareholder Alan is allocated an S corporation loss for the year, which cannot be used because of the basis limitation. Alan will lose the unused loss if not used by

A) December 31 of this year.

B) March 15 of next year.

C) October 31 of next year.

D) December 31 of next year.

Answer: C

Page Ref.: C:11-23; Example C:11-20

Objective: 5

60) Identify which of the following statements is false.

A) Randy is a shareholder in an S corporation. His stock basis is $10,000 and his basis in a loan he made

to the corporation is $3,000. Randy's share of the corporation's ordinary loss for the current year is $11,000. Ignoring the at-risk and passive activity limitations, Randy can deduct the loss in full.

B) A shareholder's S corporation stock basis will increase when the shareholder acts as guarantor on a corporate indebtedness.

C) A shareholder's ratable share of the S corporation's ordinary loss reduces the adjusted basis of his/her S corporation stock. Once the basis of the stock is reduced to zero, any loss-passthrough that remains reduces the basis of S corporation debts that are owed to the shareholder.

D) Debt basis is restored before stock basis.

Answer: B

Page Ref.: C:11-25 and C:11-26

Objective: 5

61) An S corporation reports ordinary income of $120,000 after deducting $20,000 for Fred's salary. Fred and his three children own the S corporation equally. The IRS determines Fred's stock transfer to his three children is not bona fide. Reasonable compensation for Fred is $40,000. How much of the S corporation's $140,000 pre-salary income must be reported by Fred?

A) $140,000

B) $100,000

C) $50,000

D) $40,000

Answer: A

Page Ref.: C:11-24; Example C:11-21

Objective: 5

62) Identify which of the following statements is false.

A) The AAA balance can be negative, but the shareholder's basis in the S corporation stock cannot be less than zero.

B) The AAA represents the cumulative income/loss recognized in post-1982 S corporation years.

C) Nonmoney property distributions made by an S corporation having accumulated E&P are treated differently when determining the corporate-level gain recognized under Sec. 311 than are property distributions made by an S corporation without accumulated E&P.

D) Tax-exempt income does not increase the AAA but increases the basis of the S corporation stock. Answer: C

Page Ref.: C:11-27 through C:11-29

Objective: 7

63) Pressley Corporation was incorporated on January 1, 2004. The corporation made its S election on March 1, 2008. The corporation retains an E&P balance from its C corporation days. During the current year, it made a cash distribution to its sole shareholder Robert Pressley. What is the proper sequence in reducing the corporate earnings accounts for the distribution?

A) AAA; E&P

B) AAA; OAA; E&P

C) E&P; AAA

D) AAA; PTI; E&P

Answer: A

Explanation: A) The OAA is not a separate accumulated earnings account even though it is reported on page 4 of the Form 1120S. The tax-exempt income otherwise included in OAA becomes part of the S corporation's stock basis for distribution purposes.

Page Ref.: C:11-30

Objective: 7

64) Dixon Corporation was incorporated on January 1, 2005. The corporation made its S election on April 1, 2008. The corporation retains an E&P balance from its C corporation days. Which one of the following current-year income and expense items is not included in Dixon Corporation's Accumulated Adjustments Account?

A) ordinary income or loss

B) tax-exempt bond interest income

C) long-term capital gains and losses

D) amortization of organizational expenditures

Answer: B

Explanation: B) The tax-exempt bond interest income is included in the Other Adjustments Account. Page Ref.: C:11-30

Objective: 7

65) Identify which of the following statements is true.

A) An S corporation may be subject to the corporate alternative minimum tax.

B) Allocation of tax preference items for AMT generally occurs on a daily basis.

C) An S corporation may be subject to the corporate alternative minimum tax when the corporation has accumulated E&P from prior C corporation tax years.

D) All of the above are false.

Answer: B

Page Ref.: C:11-33

Objective: 7

66) Identify which of the following statements is true.

A) Fringe benefits limited by the more-than-2%-shareholder rule include stock options, group term life insurance premiums, and medical insurance premiums.

B) A shareholder owning 2% or more of an S corporation's stock, who is also an employee of the corporation, must include all statutory fringe benefits in gross income on his/her individual return.

C) Section 318 stock attribution rules are used to define 2% or more shareholders of S corporation's stock.

D) All of the above are false.

Answer: B

Page Ref.: C:11-33 and C:11-34

Objective: 7

67) An S corporation is not treated as a corporate taxpayer with respect to which one of the following fringe benefits?

A) stock options

B) qualified retirement plans

C) group term life insurance premiums

D) nonqualified deferred compensation

Answer: C

Page Ref.: C:11-34

Objective: 7

68) Identify which of the following statements is false.

A) The election form can be signed by a person authorized to sign the S corporation tax return.

B) An S election is filed by the corporation by using Form 2553 on or before the due date (without regard to any extensions) for the corporate tax return for the tax year in question.

C) An S corporation must file a tax return for any year in which the S corporation is in existence.

D) The IRS can grant extensions of time of filing shareholder consents to the S election.

Answer: B

Page Ref.: C:11-37

Objective: 7

69) Identify which of the following statements is false.

A) An S corporation files a Form 1120S corporate income tax return on or before the 15th day of the fourth month following the close of its tax year.

B) An S corporation's ordinary income or loss is reported by an individual shareholder on Schedule E of Form 1040.

C) An S corporation that owes the built-in gains tax or the excess net passive income tax must make quarterly estimated tax payments.

D) An S corporation cannot use the prior-year tax liability exception when determining the required payment to be made with respect to the built-in gains tax.

Answer: A

Page Ref.: C:11-37 and C:11-38

Objective: 10

70) Mashburn Corporation is an S corporation that uses a fiscal year ending June 30 as its tax year. When is Mashburn Corporation's income tax return due?

A) July 15

B) September 15

C) October 15

D) March 15 of the next year

Answer: B

Page Ref.: C:11-37

Objective: 10

71) An S corporation is permitted an automatic extension of time for filing its tax return. The automatic extension period is

A) one month.

B) two months.

C) three months.

D) six months.

Answer: D

Page Ref.: C:11-37

Objective: 10

72) Which of the following tax levies imposed on an S corporation are required to be paid by using estimated tax payments?

A) built-in gains tax

B) excess net passive income tax

C) both A and B

D) none of the above

Answer: C

Page Ref.: C:11-38

Objective: 10

73) Connie's Restaurant has been an S corporation since it was formed in 2006. Its results for the previous year are as follows:

Sales $200,000

Supplies 90,000

Salaries 50,000

Depreciation 5,000

Interest on business loan 1,000

Charitable contributions 3,000

Advertising 4,000

Utilities expense 6,000

Property taxes 1,000

Gain on the sale of

investment land (long-term) 8,000

What are Connie's separately stated items? What is the S corporation's ordinary income?

Answer: The separately stated items, other than ordinary income, are the long-term capital gain of $8,000 and the charitable contributions. The S corporation ordinary income is calculated as follows:

Sales $200,000

Supplies 90,000

Salaries (employees) 50,000

Depreciation 5,000

Interest on business loan 1,000

Advertising 4,000

Utilities expense 6,000

Property taxes 1,000 157,000

Ordinary income $43,000

Page Ref.: C:11-14 and 11-15

Objective: 4

74) Power Corporation reports the following results:

Service income (not passive income) $40,000

Dividend income 30,000

Interest income 60,000

Passive income-related expenses 20,000

Other expenses 50,000

At the end of the year, Power's Subchapter C E&P is $50,000. What is Power Corporation's excess net passive income and its excess net passive income tax for the year?

Answer: The excess net passive income is:

{[$30,000 + $60,000 - $20,000] × [$90,000 - (0.25 × $130,000)]/$90,000} = $44,722.

The excess net passive income tax is: $44,722 × 0.35 = $15,653.

Page Ref.: C:11-16

Objective: 4

75) Chuck Corporation reports the following results for this year:

Service (nonpassive) income $17,500

Dividend income 18,500

Interest income 14,000

Passive income-related expenses 5,000

Other expenses 12,500

At the end of this year, Chuck's E&P for its C corporation tax years amount to $30,000. Compute Chuck Corporation's excess net passive income.

Answer: Excess net passive income = Net Passive income x

income

investment Passive receipts gross of 25% - income investment Passive

$16,913 = ($32,500 - $5,000) ×

500

,32$0)25%($50,00 - $32,500 Page Ref.: C:11-16

Objective: 4 76) Potter Corporation reports the following results for the current year:

Operating income $40,000

Dividend income 35,000

Interest income 25,000

Other expenses 25,000

Passive income-related expenses 20,000

At the end of the year, Potter's Subchapter C E&P is $50,000. What is the amount of Potter's excess net passive income?

Answer: $35,000 Dividends

25,000 Interest

$60,000 Gross passive income

( 20,000) Minus: related expenses $40,000 Net passive income

Excess net passive income =

000

,60$$100,000) x (0.25 - $60,000 × $40,000 = $23,333 Page Ref.: C:11-16

Objective: 4

77) Boxer Corporation, a C corporation, elects on June 30 of last year to make an S election for the current year. The net unrealized built-in gains at the beginning of the current year are $300,000. The net recognized built-in gains in the current year are $110,000. What is Boxer's built-in gains tax for the current year?

Answer: $110,000 × 0.35 = $38,500

Page Ref.: C:11-17

Objective: 4

78) Gofer Corporation, an S corporation, is owned equally by Mahmoud and Kwame. The corporation had long-term capital gains of $100,000 and ordinary income of $90,000 for the current year and made no distributions. What is the amount of ordinary income from S corporation activities that Mahmoud must report?

Answer: $90,000 × 0.50 = $45,000

Page Ref.: C:11-19

Objective: 5

79) For the calendar year, Elk Corporation, an S corporation, has book income of $55,000, which includes $45,000 from operations and a $10,000 net long-term capital gain. During the year, $22,500 is distributed to Elk's three equal shareholders, all of whom are calendar-year taxpayers. What are Elk's total ordinary income and capital gain pass-throughs for the year?

Answer: Ordinary income is $45,000 and long-term capital gain income is $10,000.

Page Ref.: C:11-19

Objective: 5

80) The Vanity Corporation organized and began operations in January. The corporation's ten equal shareholders elect to have Vanity taxed as an S corporation, and the election and necessary consents are filed in a timely manner. For its first tax year ended December 31, Vanity has ordinary income of $64,000 and short-term capital gains of $16,000. During the year, it distributes $30,000 in cash equally to its ten shareholders. For the year, how much income should each shareholder report and how should it be characterized?

Answer: Ordinary income, $6,400 (0.10 × $64,000).

Short-term capital gain, $1,600 (0.10 × $16,000).

The distribution does not result in any income or gain being recognized since it does not exceed any shareholder's basis for their stock.

Page Ref.: C:11-19 through C:11-24

Objective: 5

霍尔电流传感器的应用场合

霍尔电流传感器的应用场合 1、继电保护与测量：在工业应用中，来自高压三相输电线路电流互感器的二次电流，如分别经三只霍尔电流传感器，按比例转换成毫伏电压输出，然后再经运算放大器放大及有源滤波，得到符合要求的电压信号，可送微机进行测量或处理。在这里使用霍尔电流传感器可以很方便地实现了无畸变、无延时的信号转换。 2、在直流自动控制调速系统中的应用：在直流自动控制调速系统中，用霍尔电流电压传感器可以直接代替电流互感器，不仅动态响应好，还可实现对转子电流的最佳控制以及对晶闸管进行过载保护。 3、在逆变器中的应用：在逆变器中，用霍尔电流传感器可进行接地故障检测、直接侧和交流侧的模拟量传感，以保证逆变器能安全工作。 4、在不间断电源中的应用：在该应用中，用霍尔电流传感器进行控制，保证逆变电源正常工作。使用霍尔电流传感器1发出信号并进行反馈，以控制晶闸管的触发角，霍尔电流传感器2发出的信号控制逆变器，霍尔电流传感器3控制浮充电源。由于其响应速度快，霍尔电流传感器特别适用于计算机中的不间断电源。 5、在电子点焊机中的应用：在电子点焊机电源中，霍尔电流传感器起测量和控制作用。它的快速响应能再现电流、电压波形，将它们反馈到可控整流器A、B，可控制其输出。用斩波器给直流迭加上一个交流，可更精确地控制电流。用霍尔电流传感器进行电流检测，既可测量电流的真正瞬时值，又不致引入损耗。 6、用于电车斩波器的控制：电车中的调速是由调整电压实现的。而将霍尔电流传感器和其它元件配合使用，并将传感器的所有信号输入控制系统，可确保电车正常工作。 7、在交流变频调速电机中的应用：用变频器来对交流电机实施调速，在世界各发达国家已普遍使用，且有取代直流调速的趋势。用变频器控制电机实现调速，可节省10％以上的电能。在变频器中，霍尔电流传感器的主要作用是保护昂贵的大功率晶体管。由于霍尔电流传感器的响应时间往往小于5μs，因此，出现过载短路时，在晶全管未达到极限温度之前即可切断电源，使晶体管得到可靠的保护。 8、用于电能管理：霍尔电流传感器，可安装到配电线路上进行负载管理。霍尔电流传感器的输出和计算机连接起来，对用电情况进行监控，若发现过载，便及时使受控的线路断开，保证用电设备的安全。用这种装置，也可进行负载分配及电网的遥控、遥测和巡检等。

密度表观密度体积密度和堆积密度

密度、表观密度、体积密度和堆积密度 密度是指材料在绝对密实状态下单位体积的质量。表观密度是材料在包括闭口孔隙条件下单位体积的质量。体积密度是指材料在自然状态下的体积，包括材料实体及其开口与闭口孔隙条件下的单位体积的质量。堆积密度是指散粒或纤维状材料在堆积状态下单位体积的质量。密度、表观密度、体积密度和堆积密度既有联系又有差别。 材料的孔隙率是指材料内部孔隙的体积占材料总体积的百分率。空隙率则是指散粒状材料在堆积体积状态下颗粒固体物质间空隙体积(开口孔隙与间隙之和)占堆积体积的百分率。材料的孔隙有闭口和开口，其特征状态对材料的性质有重要影响。 材料内部孔隙示意 密度 密度是指材料在绝对密实状态下单位体积的质量。按下式计算： 式中ρ——材料的密度，g/cm3； m——材料的质量（干燥至恒重），g； V——材料在绝对密实状态下的体积，cm3。 除了钢材，玻璃等少数材料外，绝大多数材料内部都有一些孔隙。在测定有孔隙材料（如砖、石等）的密度时，应把材料磨成细粉，干燥后，用李氏瓶测定其绝对密实体积。材料磨得越细，测得的密实体积数值就越精确。 另外，工程上还经常用到比重的概念，比重又称相对密度，是用材料的质量与同体积水（4℃）的质量的比值表示，无单位，其值与材料密度相同（g/cm3）。 表观密度 表观密度是指单位体积（含材料实体及闭口孔隙体积）物质颗粒的干质量，也称

视密度。按下式计算： 式中ρ′——材料的表观密度，kg/m3或g/cm3； m——材料的质量，kg或g； V′——材料在包含闭口孔隙条件下的体积（即只含内部闭口孔，不含开口孔），见图1-2，m3或cm3。 通常，材料在包含闭口孔隙条件下的体积式采用排液置换法或水中称重法测量。 体积密度 体积密度是指材料在自然状态下单位体积（包括材料实体及其开口孔隙、闭口孔隙）的质量，俗称容重。体积密度可按下式计算： 式中ρ0——材料的体积密度，kg/m3或g/cm3； m——材料的质量，kg或g； V0——材料在自然状态下的体积，包括材料实体及其开口孔隙、闭口孔隙，见图1－1，m3或cm3。 对于规则形状材料的体积，可用量具测得。如加气混凝土砌块的体积是逐块量取长、宽、高三个方向的轴线尺寸，计算其体积。对于不规则形状材料的体积，可

材料的密度、表观密度与堆积密度

表示材料物理状态特征的性质 1、体积密度：材料在自然状态下单位体积的质量称为体积密度。 2、密度：材料在绝对密实状态下单位体积的质量称为密度。 3、堆积密度：散粒材料在规定装填条件下单位体积的质量称为堆积密度。 注意：密实状态下的体积是指构成材料的固体物质本身的体积；自然状态下的体积是指固体物质的体积与全部孔隙体积之和；堆积体积是指自然状态下的体积与颗粒之间的空隙之和。 4、表观密度：材料的质量与表观体积之比。表观体积是实体积加闭口孔隙体积，此体积即材料排开水的体积。 5、孔隙率：材料中孔隙体积与材料在自然状态下的体积之比的百分率。 6、开口孔隙率：材料中能被水饱和（即被水所充满）的孔隙体积与材料在自然状态下的体积之比的百分率。 7、闭口孔隙率：材料中闭口孔隙的体积与材料在自然状态下的体积之比的百分率。即闭口孔隙率=孔隙率-开口孔隙率。 8、空隙率：散粒材料在自然堆积状态下，其中的空隙体积与散粒材料在自然状态下的体积之比的百分率。 什么是绝对密实状态 悬赏分：20 - 提问时间2009-8-25 20:25问题为何被关闭 建筑材料课程中有“绝对密实状态”一词，绝对密实状态是什么意思啊？ 说的细一点哦！ 提问者：秦瀛 - 四级答复共 1 条 理想状态，无孔隙的。玻璃一类的可以理想地看做绝对密实。 绝对密实状态下的体积是指不包括孔隙在内的体积，材料在自然状态下的体积减去材料内部孔隙的体积。 测量密度时，由于一般材料的内部均含有一些孔隙，为了获得绝对密实状态的试样，须将材料磨成细粉以排除其内部孔隙，再用排液置换法求出材料的绝对密实体积。 材料的密实度是指材料在绝对密实状态下的体积与在自然状态下的体积之比。凡是内部有孔隙的材料，其密实度都小于1.材料的密实度反映固体材料中固体物质的充实程度，密实度的大小与其强度、耐水性和导热性等很多性质有关。 材料的密度、表观密度与堆积密度 材料的密度、表观密度与堆积密度 1、密度：密度是材料在绝对密实状态下，单位体积的质量。——密度自身体积 （不含孔隙）磨成细粉消除内部孔隙，材料的排水体积 V 计算式ρ= m/v 式中ρ--- 材料的密度，g/㎝3 。 m --- 材料在干燥状态下的质量，g 。 v --- 材料在绝对密实状态下的体积，㎝3。

霍尔传感器用法

一、霍尔电流电压传感器、变送器的基本原理与使用方法 1．霍尔器件 霍尔器件是一种采用半导体材料制成的磁电转换器件。如果在输入端通入控 制电流I C ，当有一磁场B穿过该器件感磁面，则在输出端出现霍尔电势V H 。 如图1－1所示。 霍尔电势V H 的大小与控制电流I C 和磁通密度B的乘积成正比，即：V H ＝K H I C Bsin Θ 霍尔电流传感器是按照安培定律原理做成，即在载流导体周围产生一正比于该电流的磁场，而霍尔器件则用来测量这一磁场。因此，使电流的非接触测量成为可能。 通过测量霍尔电势的大小间接测量载流导体电流的大小。因此，电流传感器经过了电－磁－电的绝缘隔离转换。 2．霍尔直流检测原理 如图1－2所示。由于磁路与霍尔器件的输出具有良好的线性关系，因此霍尔 器件输出的电压讯号U 0可以间接反映出被测电流I 1 的大小，即：I 1 ∝B 1 ∝U 我们把U 0定标为当被测电流I 1 为额定值时，U 等于50mV或100mV。这就制成 霍尔直接检测（无放大）电流传感器。

3．霍尔磁补偿原理 原边主回路有一被测电流I1，将产生磁通Φ1，被副边补偿线圈通过的电流I2所产生的磁通Φ2进行补偿后保持磁平衡状态，霍尔器件则始终处于检测零磁通的作用。所以称为霍尔磁补偿电流传感器。这种先进的原理模式优于直检原理模式，突出的优点是响应时间快和测量精度高，特别适用于弱小电流的检测。霍尔磁补偿原理如图1－3所示。 从图1－3知道：Φ 1＝Φ 2 I 1N 1 ＝I 2 N 2 I 2＝N I /N 2 ·I 1 当补偿电流I 2流过测量电阻R M 时，在R M 两端转换成电压。做为传感器测量电 压U 0即：U ＝I 2 R M 按照霍尔磁补偿原理制成了额定输入从0.01A～500A系列规格的电流传感器。 由于磁补偿式电流传感器必须在磁环上绕成千上万匝的补偿线圈，因而成本增加；其次，工作电流消耗也相应增加；但它却具有直检式不可比拟的较高精度和快速响应等优点。 4．磁补偿式电压传感器 为了测量mA级的小电流，根据Φ 1＝I 1 N 1 ，增加N 1 的匝数，同样可以获得高磁 通Φ 1 。采用这种方法制成的小电流传感器不但可以测mA级电流，而且可以测电压。 与电流传感器所不同的是在测量电压时，电压传感器的原边多匝绕组通过串 联一个限流电阻R 1，然后并联连接在被测电压U 1 上，得到与被测电压U 1 成比 例的电流I 1 ，如图1－4所示。

霍尔电流传感器及其应用

霍尔电流传感器及其应用 在现代社会中,信息化的需求越来越庞大，传感器在信息采集中发挥了重要作用。他们可以把各种物理信息，按照一定的规则，为可测量的电信号。我们所测量的电信号，以及相关物理信息的关系的变化的基础上，我们可以得到所测量的物理的变化或大小。 根据该传感器的工作原理，我们可以划分成多种类型的传感器，如光电传感器，电荷传感器，电位型传感器，半导体传感器，电传感器，磁传感器，谐振式传感器，电动化学式传感器等等。 霍尔传感器是利用霍尔元件的霍尔效应原理，（可以音乐会的物理信息），如电流，磁场，位移，压力等，为电动势输出。它属于电位型传感器。当前，这种传感器主要是霍尔集成电路，核心单元是基于霍尔效应。这是由通过集成电路技术。因此，它不仅仅是一种集成电路，而是一种磁传感器。 本文根据实际应用，主要是霍尔电流传感器。 1 霍尔效应 在金属或半导体晶片放置在磁场中，并且如果有一个通过它的电流，会产生电动势，（在垂直方向上的电场和磁场，调用此种物理现象霍尔效应。） 在磁场中产生的洛伦兹力的作用下，通电的半导体芯片的载体，分别偏移积累到芯片的两侧，从而形成一个电场，称霍尔电场。霍尔电场产生的电场力，是相反的洛伦兹力，阻碍了继续堆积，直到（大厅）电场力和洛伦兹力。此时，芯片的两侧，将设置一个稳定的电压，这是霍尔电压。 2 霍尔电流传感器 随着城市人口和城市建设规模的扩大，以及各种电气设备的增加，功耗也越来越大。城市的供电设备经常超载，而电源环境越来越差，“测试”的权利越来越严重。因此电源问题越来越多的显现出来。现在，小功率电源设备已经越来越多的与新技术相结合。例如，开关电源，硬切换，软切换，参数稳压器，线性反馈稳压器，磁放大器技术，数控压力调节，PWM,,SPWM，电磁兼容等实际需求直接推动电源技术的发展和进步。为了检验并显示当前自动，自动保护功能和更先进的智能控制，过电流，过电压的危害。如发生时，电源技术与传感检测，传感采样，传感保护已成为一种趋势。传感器检测电流或电压，所谓的霍尔电流传感器应运而生，(并迅速成为最喜爱的设计师在我国的电源). 2.1 霍尔电流传感器的性能特性 霍尔电流传感器具有优越的性能，并且它是一种先进的电检测元件，它可以隔离主回路和电子控制电路。它有变压器和分流器的所有优点，并且在同一时间，克服了他们的缺点（变压器可以只施加的电源频率的测量，50赫兹，分流器是无法做隔离测量），使用同一个霍尔电流传感器模块检测元素，不仅可以测量AC,也可以检测直流，甚至可以检测瞬时峰值。它具有以下性能特点。 (1)测量任意波形的电流，如DC,AC乃至瞬态峰值参数测量的； (2)精度高。在工作区中的一般霍尔电流传感器模块的精度高于1%，并且是适用于任何波形测量精度； (3)线性度优于0.5%； (4)良好的动态性能。一般的电流传感器模块的动态响应时间小于7us，跟踪速度di|dt 是上述50A|us； (5)工作频段宽。它可以工作在频率范围从0到20KHZ非常好; (6)过载能力强。测量范围宽（0-10000A); (7)高可靠性。平均无故障工作是超过5*10000小时； (8)体积小，重量轻，易于安装系统，不会带来任何损失。

表观密度与堆积密度

密度、表观密度与堆积密度 (1) 密度 密度是指材料在绝对密实状态下单位体积的质量。按下式计算： 式中ρ——密度，g/cm3； m——材料的质量，g； V——材料在绝对密实状态下的体积，cm3。 绝对密实状态下的体积是指不包括孔隙在内的体积。所以材料的密度大小取决于材料的组成与材料的微观结构，当材料的组成与结构一定时，材料的密度为常数。除了钢材、玻璃等少数材料外，绝大多数材料都有一些孔隙。在测定有孔隙材料的密度时，应把材料磨成细粉，干燥后，用李氏瓶测定其实体积。材料磨得越细，测得的密度数值就越精确。砖、石材等块状材料的密度即用此法测得。 (2) 表观密度 表观密度是指材料在自然状态下单位体积的质量，按下式计算： 式中ρo——表观密度，g/cm3或kg/cm3； m——材料的质量，g或kg； V o——材料在自然状态下的体积，或称表观体积，cm3或m3。 材料的表观体积是指材料及所含内部孔隙的总体积，材料在自然状态下的质量与其含水状态关系密切，且与材料孔隙的具体构造特征

有关。故测定表观密度时，必须注明其含水情况，一般是指材料在气干状态（长期在空气中干燥）下的表观密度。在烘干状态下的表观密度，称为干表观密度。不含开口孔隙的表观密度称为视密度，以排水法测定其体积。 (3) 堆积密度 堆积密度是指粉状或粒状材料在堆积状态下单位体积的质量，按下式计算： 式中——堆积密度，kg/m3； m——材料的质量，kg； ——材料的堆积体积，m3。 测定散粒材料的堆积密度时，材料的质量是指填充在一定容器内的任意含水状态下的质量。但须注明含水率，其堆积体积是指所用容器的容积而言。因此，材料的堆积体积包含了颗粒内部的孔隙及颗粒之间的空隙。材料的堆积密度与材料的表观密度、堆积的紧密程度有关。在捣实状态下测定的堆积密度称为紧密堆积密度。 表观密度 英文名称: Apparent density

霍尔电流传感器工作原理

霍尔电流传感器工作原理 1、直放式（开环）电流传感器（CS系列） 当原边电流I P流过一根长导线时，在导线周围将产生一磁场，这一磁场的大小与流过导线的电流成正比，产生的磁场聚集在磁环内，通过磁环气隙中霍尔元件进行测量并放大输出，其输出电压V S精确的反映原边电流I P。一般的额定输出标定为4V。 2、磁平衡式（闭环）电流传感器（CSM系列） 磁平衡式电流传感器也称补偿式传感器，即原边电流Ip在聚磁环处所产生的磁场通过一个次级线圈电流所产生的磁场进行补偿，其补偿电流Is精确的反映原边电流Ip，从而使霍尔器件处于检测零磁通的工作状态。 具体工作过程为：当主回路有一电流通过时，在导线上产生的磁场被磁环聚集并感应到霍尔器件上，所产生的信号输出用于驱动功率管并使其导通，从而获得一个补偿电流Is。这一电流再通过多匝绕组产生磁场，该磁场与被测电流产生的磁场正好相反，因而补偿了原来的磁场，使霍尔器件的输出逐渐减小。当与Ip与匝数相乘所产生的磁场相等时，Is不再增加，这时的霍尔器件起到指示零磁通的作用，此时可以通过Is来测试Ip。当Ip变化时，平衡受到破坏，霍尔器件有信号输出，即重复上述过程重新达到平衡。被测电流的任何变化都会破坏这一平衡。一旦磁场失去平衡，霍尔器件就有信号输出。经功率放大后，立即就有相应的电流流过次级绕组以对失衡的磁场进行补偿。从磁场失衡到再次平衡，所需的时间理论上不到1μs，这是一个动态平衡的过程。因此，从宏观上看，次级的补偿电流安匝数在任何时间都与初级被测电流的安匝数相等。 3、霍尔电压（闭环）传感器（VSM系列）

霍尔电压传感器的工作原理与闭环式电流传感器相似，也是以磁平衡方式工作的。原边电压VP通过限流电阻Ri产生电流，流过原边线圈产生磁场，聚集在磁环内，通过磁环气隙中霍尔元件输出信号控制的补偿电流IS流过副边线圈产生的磁场进行补偿，其补偿电流IS精确的反映原边电压VP。 4、交流电流传感器（A-CS系列） 交流电流传感器主要测量交流信号灯电流。是将霍尔感应出的交流信号经过AC-DC及其他转换，变为0～4V、0～20mA（或4～20mA）的标准直流信号输出供各种系统使用。

细集料表观密度堆积密度及空隙率

细集料表观密度、堆积密度及空隙率 一、表观密度 1.仪器设备： 本试验用仪器设备如下： a）鼓风干燥箱：能使温度控制在（105±5）℃； b）天平：称量1000g，感量0.1g； c）容量瓶：500ml； d）干燥器、搪瓷盘、滴管、毛刷、温度计等。 2.实验步骤： 1）按规定取样方法取样，并将试样缩分至约660g，放在干燥箱中于（105±5）℃ 下烘干至恒重，待冷却至室温后，分为大致相等的两份备用。 2）称取试样300g，精确至0.1g。将试样装入容量瓶，注入冷开水至接近500ml 的刻度线处，用手旋转摇动容量瓶，使砂样充分摇动，排除气泡，塞紧瓶盖，静 置24h。然后用滴管小心加水至容量瓶500ml刻度处，塞紧瓶盖，擦干瓶外水分，称出其质量，精确至1g。 3）倒出瓶内水和试样，洗净容量瓶，再向容量瓶内注水（应与步骤“2）”水温 相差不超过2℃，并在15℃～25℃范围内）至500ml刻度处，塞紧瓶塞，擦干瓶 外水分，称出其质量，精确至1g。 注：在砂的表观密度试验过程中应测量并控制水的温度，试验的各项称量可在15℃～25℃的温度范围内进行。从试样加水静置的最后2h起直至 试验结束，其温度相差不应超过2℃。 3.结果计算与评定： 1）砂的表观密度按下式计算，精确至10kg/m3: 2）表观密度取两次试验结果的算术平均值，精确至10kg/m3；如两次试验结果之 差大于20kg/m3，应重新试验。 3）采用修约值比较法进行评定。

二、堆积密度与空隙率 1.仪器设备： 本试验用仪器设备如下： a）鼓风干燥箱：能使温度控制在（105±5）℃； b）天平：称量1000g，感量0.1g； c）容量筒：圆柱形金属筒，内经108mm，净高109mm，壁厚2mm，筒底厚约5mm，容积为1L； d）方孔筛：孔径为4.75mm的筛一只； e）垫棒：直径10mm，长500mm的圆钢； f）直尺、漏斗或料勺、搪瓷盘、毛刷等。 2.试验步骤： 1）按照规定取样方法取样，用搪瓷盘装取试样约3L，放在干燥箱中于（105±5）℃下烘干至恒重，待冷却至室温后，筛除大于4.75mm的颗粒，分为大致相等的两份备用。 2）松散堆积密度：取试样一份，用漏斗或料勺将试样从容量筒中心上方50mm 处徐徐倒入，让试样以自由落体落下，当容量筒上部试样呈椎体，且容量筒四周溢满时，即停止加料。然后用直尺沿筒口中心线向两边刮平（试验过程应防止触动容量筒），称出试样和容量筒总质量，精确至1g。 3）紧密堆积密度：取式样一份分为二次装入容量筒。装完第一层后（约计稍高于1/2），在筒底垫放一根直径为10mm的圆钢，将筒按住，左右交替击地面各25下。然后装入第二层，第二层装满后用同样方法颠实（但筒底所垫钢筋的方向与第一层时的方向垂直）后，再加试样直至超过筒口，然后用直尺沿筒口中心线向两边刮平，称出试样和容量筒总质量，精确至1g。 3.结果计算与评定： 1）松散或紧密堆积密度按下式计算，精确至10kg/m3: 2）空隙率按下式计算，精确至1%： 3）堆积密度取两次试验结果的算术平均值，精确至10kg/m3。空隙率取两次试验结果的算术平均值，精确至1%。

霍尔电流传感器的应用

霍尔电流传感器的应用 霍尔电流传感器广泛应用在变频调速装置、逆变装置、UPS电源、通信电源、电焊机、电力机车、变电站、数控机床、电解电镀、微机监测、电网监测等需要隔离检测电流的设施中以及新兴的太阳能、风能和地铁轨道信号、汽车电子等领域。 1、继电保护与测量： 在工业应用中，来自高压三相输电线路电流互感器的二次电流，如分别经三只霍尔电流传感器，按比例转换成毫伏电压输出，然后再经运算放大器放大及有源滤波，得到符合要求的电压信号，可送微机进行测量或处理。在这里使用霍尔电流传感器可以很方便地实现了无畸变、无延时的信号转换。 2、在直流自动控制调速系统中的应用： 在直流自动控制调速系统中，用霍尔电流电压传感器可以直接代替电流互感器，不仅动态响应好，还可实现对转子电流的最佳控制以及对晶闸管进行过载保护。 3、在逆变器中的应用： 在逆变器中，用霍尔电流传感器可进行接地故障检测、直接测和交流测的模拟量传感，以保证逆变器能安全工作。 4、在不间断电源中的应用： 在该应用中，用霍尔电流传感器进行控制，保证逆变电源正常工作。使用①霍尔电流传感器发出信号并进行反馈，以控制晶闸管的触发角，②霍尔电流传感器发出的信号控制逆变器，③

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简单易懂的霍尔电流传感器使用原理及相关霍尔型

简单易懂的霍尔电流传感器使用原理及相关霍 尔型 集团公司文件内部编码：（TTT-UUTT-MMYB-URTTY-ITTLTY-

1、开环（直放式）霍尔电流传感器 当原边电流I P 流过一根长导线时，在导线周围将产生一磁场，这一磁场的大小与流过导线的电流成正比，产生的磁场聚集在磁环内，通过磁环气隙中霍尔元件（如HG-302C） 进行测量并放大输出，其输出电压V S 精确的反映原边电流I P 。一般的额定输出标定为 4V。开环霍尔电流传感器的优点是结构简单，可靠性好，过载能力强，体积较小，开环式霍尔电流传感器一般线性度角差，且原边信号在上升和下降过程中副边输出会有不同。开环式霍尔电流传感器精度通常劣于1%。?一般开环电流传感器采用的霍尔是HG-106A,HG-106C,HG-166A,HG-302A,HG-302C,HG-362A,SS495A,SS495A1。 2、闭环（磁平衡式）霍尔电流传感器 磁平衡式电流传感器也称补偿式传感器，即原边电流Ip在聚磁环处所产生的磁场通过一个次级线圈电流所产生的磁场进行补偿，其补偿电流Is精确的反映原边电流Ip，从而使霍尔器件（如HW-300B,HW-302B）处于检测零磁通的工作状态。 当主回路有一电流通过时，在导线上产生的磁场被磁环聚集并感应到霍尔器件上，所产生的信号输出用于驱动功率管并使其导通，从而获得一个补偿电流Is。这一电流再通过多匝绕组产生磁场，该磁场与被测电流产生的磁场正好相反，因而补偿了原来的磁场，使霍尔器件的输出逐渐减小。当与Ip与匝数相乘所产生的磁场相等时，Is不再增加，这时的霍尔器件起到指示零磁通的作用，此时可以通过Is来测试Ip。当Ip变化时，平衡受到破坏，霍尔器件有信号输出，即重复上述过程重新达到平衡。被测电流的任何变化都会破坏这一平衡。一旦磁场失去平衡，霍尔器件（HW-300B,HW-302B）就有信号输出。经功率放大后，立即就有相应的电流流过次级绕组以对失衡的磁场进行补偿。从磁场失衡到再次平衡，所需的时间理论上不到1μs，是一个动态平衡的过程。因此，宏观上看，次级的补

简单易懂的霍尔电流传感器使用原理及相关霍尔型

简单易懂的霍尔电流传感器使用原理及相关霍尔型 This model paper was revised by the Standardization Office on December 10, 2020

简单易懂的霍尔电流传感器使用原理及相关霍尔型号推荐 1、开环（直放式）霍尔电流传感器 当原边电流I P 流过一根长导线时，在导线周围将产生一磁场，这一磁场的大小与流过导线的电流成正比，产生的磁场聚集在磁环内，通过磁环气隙中霍尔元件（如HG-302C） 进行测量并放大输出，其输出电压V S 精确的反映原边电流I P 。一般的额定输出标定为 4V。开环霍尔电流传感器的优点是结构简单，可靠性好，过载能力强，体积较小，开环式霍尔电流传感器一般线性度角差，且原边信号在上升和下降过程中副边输出会有不同。开环式霍尔电流传感器精度通常劣于1%。一般开环电流传感器采用的霍尔是HG-106A,HG-106C,HG-166A,HG-302A,HG-302C,HG-362A,SS495A,SS495A1。 2、闭环（磁平衡式）霍尔电流传感器 磁平衡式电流传感器也称补偿式传感器，即原边电流Ip在聚磁环处所产生的磁场通过一个次级线圈电流所产生的磁场进行补偿，其补偿电流Is精确的反映原边电流Ip，从而使霍尔器件（如HW-300B, HW-302B）处于检测零磁通的工作状态。 当主回路有一电流通过时，在导线上产生的磁场被磁环聚集并感应到霍尔器件上，所产生的信号输出用于驱动功率管并使其导通，从而获得一个补偿电流Is。这一电流再通过多匝绕组产生磁场，该磁场与被测电流产生的磁场正好相反，因而补偿了原来的磁场，使霍尔器件的输出逐渐减小。当与 Ip与匝数相乘所产生的磁场相等时，Is不再增加，这时的霍尔器件起到指示零磁通的作用，此时可以通过Is来测试Ip。当Ip变化时，平衡受到破坏，霍尔器件有信号输出，即重复上述过程重新达到平衡。被测电流的任何变化都会破坏这一平衡。一旦磁场失去平衡，霍尔器件（HW-300B,HW-302B）就有信号输出。经功率放大后，立即就有相应的电流流过次级绕组以对失衡的磁场进行补偿。从磁场失衡到再次平衡，所需的时间理论上不到1μs，是一个动态平衡的过程。因此，宏观上看，次级的补偿电流安匝数在任何时间都与初级被测电流的安匝数相等。一般来说闭环式电流传感器比开环电流传感器的精度更高，闭环霍尔电流传感器等特点是精度高，响应快，频带宽。闭环式霍尔电流传感器由于工作在零磁通状态，磁芯的非线性及磁滞效应不对输出造成影响，可以获得较好的线性度和较高的精度。闭环式霍尔电流传感器精度一般可达%。 闭环霍尔电流传感器一般采用的霍尔是HW-300B,HW-302B,HW-322B。

浅析霍尔电流传感器的应用

浅析霍尔电流传感器的应用 2006-6-26 15:35:00转自《仪器仪表交易网》供稿 一、前言伴随着城市人口和建设规模的扩大，各种用电设备的增多，用电量越来越大，城市的供电设备经常超负荷运转，用电环境变得越来越恶劣，对电源的“考验”越来越严重。据统计，每天，用电设备都要遭受120次左右各种的电源问题的侵扰，电子设备故障的60%来自电源.因此，电源问题的重要性日益凸显出来。原先作为配角，资金投入较少的电源越来越受到厂商和研究人员的重视，电源技术遂发展成为一门崭新的技术。 而今，小小的电源设备已经融合了越来越多的新技术。例如开关电源、硬开关、软开关、参数稳压、线性反馈稳压、磁放大器技术、数控调压、PWM、SPWM、电磁兼容等等。实际需求直接推动电源技术不断发展和进步，为了自动检测和显示电流，并在过流、过压等危害情况发生时具有自动保护功能和更高级的智能控制，具有传感检测、传感采样、传感保护的电源技术渐成趋势，检测电流或电压的传感器便应运而生并在我国开始受到广大电源设计者的青睐，本文主要介绍南京中旭电子科技有限公司的电流传感器。 二、电流传感器的工作原理 南京中旭电子科技有限公司的电流传感器可以测量各种类型的电流，从直流电到几十千赫兹的交流电，其所依据的工作原理主要是霍尔效应原理。（本文下面多以以零磁通闭环产品原理为例） 当原边导线经过电流传感器时，原边电流IP会产生磁力线，原边磁力线集中在磁芯气隙周围，内置在磁芯气隙中的霍尔电片可产生和原边磁力线成正比的，大小仅为几毫伏的感应电压，通过后续电子电路可把这个微小的信号转变成副边电流IS，并存在以下关系式：IS* NS= IP*NP 其中，IS—副边电流； IP—原边电流； NP—原边线圈匝数； NS—副边线圈匝数； NP/NS—匝数比，一般取NP=1。 电流传感器的输出信号是副边电流IS，它与输入信号（原边电流IP）成正比，IS一般很小，只有10~40 0mA。如果输出电流经过测量电阻RM，则可以得到一个与原边电流成正比的大小为几伏的电压输出信号。 2、传感器供电电压VA VA指电流传感器的供电电压，它必须在传感器所规定的范围内。超过此范围，传感器不能正常工作或可靠性降低，另外，传感器的供电电压VA又分为正极供电电压VA+和负极供电电压VA-。要注意单相供电的传感器，其供电电压VAmin是双相供电电压VAmin的2倍，所以其测量范围要相供高于双电的传感器。 3、测量范围Ipmax 测量范围指电流传感器可测量的最大电流值，测量范围一般高于标准额定值IPN。 三、电流传感器主要特性参数 1、标准额定值IPN和额定输出电流ISNIPN指电流传感器所能测试的标准额定值，用有效值表示（A.r. m.s），IPN的大小与传感器产品的型号有关。ISN指电流传感器额定输出电流，一般为10~400mA，当然根据某些型号具体可能会有所不同。 2、偏移电流ISO 偏移电流也叫残余电流或剩余电流，它主要是由霍尔元件或电子电路中运算放大器工作状态不稳造成的。电流传感器在生产时，在25℃，IP=0时的情况下，偏移电流已调至最小，但传感器在离开生产线时，都会产生一定大小的偏移电流。产品技术文档中提到的精度已考虑了偏移电流增加的影响。

霍尔电流传感器的应用

霍尔电流传感器的应用 霍尔电流传感器的应用 霍尔电流传感器的应用场合1、在逆变器中的应用：在逆变器中，用霍尔电流传感器可进行接地故障检测、直接侧和交流侧的模拟量传感，以保证逆变器能安全工作。2、在直流自动控制调速系统中的应用：在直流自动控制调速系统中，用霍尔电流电压传感器可以直接代替电流互感器，不仅动态响应好，还可实现对转子电流的最佳控制以及对晶闸管进行过载保护。3、继电保护与 测量：在工业应用中，来自高压三相输电线路电流互感器的二次电流，如分别经三只霍尔电流传感器，按比例转换成毫伏电压输出，然后再经运算放大器放大及有源滤波，得到符合要求的电压信号，可送微机进行测量或处理。在这里使用霍尔电流传感器可以很方便地实现了无畸变、无延时的信号转换。 4、在不间断电源中的应用：在该应用中，用霍尔电流传感器进行控制，保证逆变电源正常工作。使用霍尔电流传感器1 发出信号并进行反馈，以控制晶闸管的触发角，霍尔电流传感器2 发出的信号控制逆变器，霍尔电流传感器3 控制浮充电源。由于其响应速度快，霍尔电流传感器特别适用于计算机中的不间断电源。 5、在电子点焊机中的应用：在电子点焊机电源中，霍尔电流传感器起测量和控制作用。它的快速响应能再现电流、电压波形，将它们反馈到可控整流器A、B，可控制其输出。用斩波器给直流迭加上一个交流，可更精 确地控制电流。用霍尔电流传感器进行电流检测，既可测量电流的真正瞬时值，又不致引入损耗。 6、用于电车斩波器的控制：电车中的调速是由调整电压实现的。而将霍尔电流传感器和其它元件配合使用，并将传感器的所有信号输入控制系统，可确保电车正常工作。 7、在交流变频调速电机中的应用：用变频器来对交流电