Prentice hall's federal taxation test bank Ind.chapter 1

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

Individuals

Chapter I1 An Introduction to Taxation

1) The federal income tax is the dominant form of taxation by the federal government.

Answer: TRUE

Page Ref.: I:1-2

Objective: 1

2) The Sixteenth Amendment permits the passage of a federal income tax.

Answer: TRUE

Page Ref.: I:1-2

Objective: 1

3) When a change in the tax law is deemed necessary by Congress, the entire Internal Revenue Code must be revised.

Answer: FALSE

Explanation: The federal income tax law is changed on an incremental basis.

Page Ref.: I:1-3

Objective: 1

4) A progressive tax rate structure is one where the rate of tax increases as the tax base increases. Answer: TRUE

Page Ref.: I:1-4

Objective: 2

5) The terms "progressive tax" and "flat tax" are synonymous.

Answer: FALSE

Explanation: A proportional tax and flat tax are synonymous.

Page Ref.: I:1-4

Objective: 2

6) A proportional tax rate is one where the rate of the tax is the same for all taxpayers, regardless of income levels.

Answer: TRUE

Page Ref.: I:1-4

Objective: 2

7) Regressive tax rates decrease as the tax base increases.

Answer: TRUE

Page Ref.: I:1-5

Objective: 2

8) The marginal tax rate is useful in tax planning because it measures the tax effect of a proposed transaction.

Answer: TRUE

Page Ref.: I:1-5

Objective: 2

9) A taxpayer's average tax rate is the tax rate applied to an incremental amount of taxable income that is added to the tax base.

Answer: FALSE

Explanation: The marginal tax rate is the tax rate applied to an incremental amount of taxable income. Page Ref.: I:1-5

Objective: 2

10) If a taxpayer's total tax liability is $30,000, taxable income is $100,000, and economic income is $120,000, the average tax rate is 30 percent.

Answer: TRUE

Page Ref.: I:1-5

Objective: 2

11) If a taxpayer's total tax liability is $4,000, taxable income is $20,000, and total economic income is $40,000, then the effective tax rate is 20 percent.

Answer: FALSE

Explanation: The effective rate would be $4,000/$40,000 = 10 percent.

Page Ref.: I:1-6

Objective: 2

12) All states impose a state income tax which is generally based on an individual's federal adjusted gross income (AGI) with minor adjustments.

Answer: FALSE

Explanation: While many states impose a state income tax, not all states do. In those states that do impose tax, the taxes vary greatly in both form and rates.

Page Ref.: I:1-7

Objective: 3

13) The unified transfer tax system, comprised of the gift and estate taxes, is based upon the total property transfers an individual makes during lifetime and at death.

Answer: TRUE

Page Ref.: I:1-7

Objective: 3

14) Gifts between spouses are generally exempt from transfer taxes.

Answer: TRUE

Page Ref.: I:1-8

Objective: 3

15) The primary liability for payment of the gift tax is imposed upon the donee.

Answer: FALSE

Explanation: The gift tax is imposed on the donor.

Page Ref.: I:1-8

Objective: 3

16) For gift tax purposes, a $13,000 annual exclusion per donee is permitted.

Answer: TRUE

Page Ref.: I:1-8

Objective: 3

17) Property is generally valued on an estate tax return at the fair market value at the date of death or alternate valuation date.

Answer: TRUE

Page Ref.: I:1-10

Objective: 3

18) Property transferred to the decedent's spouse is exempt from the estate tax because of the estate tax marital deduction provision.

Answer: TRUE

Page Ref.: I:1-10

Objective: 3

19) Gifts made during a taxpayer's lifetime may affect the amount of estate tax paid by the taxpayer's estate.

Answer: TRUE

Page Ref.: I:1-10

Objective: 3

20) While federal and state income taxes as well as the federal gift and estate taxes are generally progressive in nature, property taxes are proportional.

Answer: TRUE

Page Ref.: I:1-11

Objective: 3

21) Adam Smith's canons of taxation are equity, certainty, convenience and economy.

Answer: TRUE

Page Ref.: I:1-11

Objective: 4

22) The primary objective of the federal income tax law is to achieve various economic and social policy objectives.

Answer: FALSE

Explanation: The primary objective of the federal income tax law is to raise revenues for government operations.

Page Ref.: I:1-14

Objective: 4

23) Individuals are the principal taxpaying entities in the federal income tax system.

Answer: TRUE

Page Ref.: I:1-17

Objective: 5

24) The various entities in the federal income tax system may be classified into two general categories, taxpaying entities (such as individuals and C [regular] corporations) and flow-through entities such as sole proprietorships, partnerships, S corporations, and limited liability companies.

Answer: TRUE

Page Ref.: I:1-17

Objective: 5

25) In 2012, dividends paid from most U.S. corporations are taxed at the same rate as the recipients' salaries and wages.

Answer: FALSE

Explanation: Qualifying dividends are taxed at a preferential rate.

Page Ref.: I:1-20

Objective: 5

26) Flow-through entities do not have to file tax returns since they are not taxable entities.

Answer: FALSE

Explanation: S Corporations, partnerships and limited liability companies do have to file an informational tax return each year.

Page Ref.: I:1-20

Objective: 5

27) S Corporations result in a single level of taxation.

Answer: TRUE

Page Ref.: I:1-22

Objective: 5

28) In a limited liability partnership, a partner is not liable for his partner's acts of negligence or misconduct.

Answer: TRUE

Page Ref.: I:1-23

Objective: 5

29) Limited liability companies may elect to be taxed as corporations.

Answer: TRUE

Page Ref.: I:1-23

Objective: 5

30) Limited liability company members (owners) are responsible for the liabilities of their limited liability company.

Answer: FALSE

Explanation: Limited liability company members have protection from entity-level liability in a manner similar to that of shareholders of corporations.

Page Ref.: I:1-23

Objective: 5

31) The tax law encompasses administrative and judicial interpretations, such as Treasury regulations, revenue rulings, revenue procedures, and court decisions, as well as statutes.

Answer: TRUE

Page Ref.: I:1-24

Objective: 6

32) Generally, tax legislation is introduced first in the Senate and referred to the Senate Finance Committee.

Answer: FALSE

Explanation: A tax bill is introduced in the House and referred to the Ways and Means Committee. Page Ref.: I:1-24

Objective: 7

33) The Internal Revenue Service is the branch of the Treasury Department responsible for administering the federal tax law.

Answer: TRUE

Page Ref.: I:1-26

Objective: 8

34) Generally, the statute of limitations is three years from the later of the date the tax return is filed or the due date.

Answer: TRUE

Page Ref.: I:1-28

Objective: 8

35) Arthur pays tax of $5,000 on taxable income of $50,000 while taxpayer Barbara pays tax of $12,000 on $120,000. The tax is a

A) progressive tax.

B) proportional tax.

C) regressive tax.

D) None of the above.

Answer: B

Explanation: B) The tax rate is proportional because the 10% tax rate applies to both taxpayers regardless of their income level.

Page Ref.: I:1-4; Example I:1-3

Objective: 2

36) Which of the following taxes is progressive?

A) sales tax

B) excise tax

C) property tax

D) income tax

Answer: D

Explanation: D) The income tax rates increase as a taxpayer's taxable income rises.

Page Ref.: I:1-4

Objective: 2

37) Which of the following taxes is proportional?

A) gift tax

B) income tax

C) sales tax

D) Federal Insurance Contributions Act (FICA)

Answer: C

Explanation: C) A sales tax is assessed at a fixed rate of the purchase amount, based on state and local law.

Page Ref.: I:1-4 and I:1-11; Topic Review I:1-1

Objective: 2

38) Which of the following taxes is regressive?

A) Federal Insurance Contributions Act (FICA)

B) excise tax

C) property tax

D) gift tax

Answer: A

Explanation: A) For upper income wage earners, the Social Security tax ceases at a maximum wage base. For 2012, wages over $110,100 are not subject to the Social Security tax.

Page Ref.: I:1-4 and I:1-11; Topic Review I:1-1

Objective: 2

39) Sarah contributes $25,000 to a church. Sarah's marginal tax rate is 35% while her average tax rate is 25%. After considering her tax savings, Sarah's contribution costs

A) $6,250.

B) $8,750.

C) $16,250.

D) $18,750.

Answer: C

Explanation: C) [$25,000 × (100% - 35%)] = $16,250

Page Ref.: I:1-5; Example I:1-4

Objective: 2

40) Helen, who is single, is considering purchasing a residence that will provide a $28,000 tax deduction for property taxes and mortgage interest. If her marginal tax rate is 25% and her effective tax rate is 20%, what is the amount of Helen's tax savings from purchasing the residence?

A) $5,600

B) $7,000

C) $21,000

D) $22,400

Answer: B

Explanation: B) $28,000 × .25 marginal rate = $7,000 tax savings.

Page Ref.: I:1-5; Example I:1-4

Objective: 2

41) Charlotte pays $16,000 in tax deductible property taxes. Charlotte's marginal tax rate is 28%, effective tax rate is 22% and average rate is 25%. Charlotte's tax savings from paying the property tax is

A) $3,520.

B) $4,000.

C) $4,480.

D) $11,520.

Answer: C

Explanation: C) $16,000 × 0.28 = $4,480

Page Ref.: I:1-5; Example I:1-4

Objective: 2

42) Anne, who is single, has taxable income for the current year of $38,000 while total economic income is $43,000 resulting in a total tax of $5,625. Anne's average tax rate and effective tax rate are, respectively,

A) 14.80% and 13.08%.

B) 13.08% and 14.80%.

C) 11.58% and 13.08%.

D) 14.80% and 13.65%.

Answer: A

Explanation: A) $5,625 ÷ $38,000 = 0.1480

$5,625 ÷ $43,000 = 0.1308

Page Ref.: I:1-6; Example I:1-5

Objective: 2

43) The unified transfer tax system

A) imposes a single tax upon transfers of property during an individual's lifetime only.

B) imposes a single tax upon transfers of property during an individual's life and at death.

C) imposes a single tax upon transfers of property only at an individual's death.

D) none of above.

Answer: B

Explanation: B) The gift (transfers during life) tax and estate (transfers after death) tax systems are unified.

Page Ref.: I:1-7

Objective: 3

44) When property is transferred, the gift tax is based on

A) replacement cost of the transferred property.

B) fair market value on the date of transfer.

C) the transferor's original cost of the transferred property.

D) the transferor's depreciated cost of the transferred property.

Answer: B

Explanation: B) The gift tax is based on the property's fair market value on the date of transfer.

Page Ref.: I:1-8

Objective: 3

45) Paul makes the following property transfers in the current year:

? $22,000 cash to his wife

? $34,000 cash to a qualified charity

? $220,000 house to his son

? $3,000 computer to an unrelated friend

The total of Paul's taxable gifts, assuming he does not elect gift splitting with his spouse, subject to the unified transfer tax is

A) $207,000.

B) $223,000.

C) $245,000.

D) $279,000.

Answer: A

Explanation: A) $220,000 - $13,000 = $207,000. The gift to the unrelated friend is below the $13,000 annual gift tax exclusion. The gifts to his wife and to the charity are not subject to gift tax.

Page Ref.: I:1-8; Example I:1-6

Objective: 3

46) Charlie makes the following gifts in the current year: $40,000 to his spouse, $30,000 to his church, $18,000 to his nephew, and $25,000 to a friend. Assuming Charlie does not elect gift splitting with his wife, his taxable gifts in the current year will be

A) $13,000.

B) $17,000.

C) $25,000.

D) $40,000.

Answer: B

Explanation: B) ($18,000 - $13,000) + (25,000 - $13,000) = $17,000. The gift to his spouse and the charitable gift are not subject to gift taxes.

Page Ref.: I:1-8; Example I:1-6

Objective: 3

47) Shaquille buys new cars for five of his friends. Each car cost $70,000. What is the amount of Shaquille's taxable gifts?

A) $0

B) $285,000

C) $337,000

D) $350,000

Answer: B

Explanation: B) (5 × $70,000) - (5 × $13,000) = 285,000

Page Ref.: I:1-8; Example I:1-6

Objective: 3

48) In 2012, an estate is not taxable unless the sum of the taxable estate and taxable gifts made after 1976 exceeds

A) $1,500,000.

B) $2,000,000.

C) $3,500,000.

D) $5,000,000.

Answer: D

Explanation: D) The unified credit equivalent for estate and gift taxes is $ 5,000,000 for 2011.

Page Ref.: I:1-9; Example I:1-7

Objective: 3

49) Eric dies in the current year and has a gross estate valued at $6,500,000. The estate incurs funeral and administrative expenses of $100,000 and also pays off Eric's debts which amount to $250,000. Eric bequeaths $600,000 to his wife. Eric made no taxable transfers during his life. Eric's taxable estate will be

A) $550,000.

B) $5,550,000.

C) $6,150,000

D) $6,500,000.

Answer: B

Explanation: B) ($6,500,000 - $100,000 - $250,000 - $600,000) = $5,550,000

Page Ref.: I:1-10; Example I:1-8

Objective: 3

50) Thomas dies in the current year and has a gross estate valued at $3,000,000. During his lifetime (but after 1976) Thomas had made taxable gifts of $400,000. The estate incurs funeral and administrative expenses of $100,000 and also pays off Thomas' debts which amount to $300,000. Thomas bequeaths $500,000 to his wife. What is the amount of Thomas' tax base, the amount on which the estate tax is computed?

A) $2,100,000

B) $2,500,000

C) $2,600,000

D) $3,400,000

Answer: B

Explanation: B) ($3,000,000 - $100,000 - $300,000 - $500,000 = $2,100,000 taxable estate + $400,000 gifts = $2,500,000 tax base)

Page Ref.: I:1-10; Example I:1-8

Objective: 3

51) Which of the following statements is incorrect?

A) Property taxes are levied on real estate.

B) Excise taxes are assessed on items such as gasoline and telephone use.

C) Gift taxes are levied on the recipient of a gift.

D) The estate tax is based on the fair market value of property at death or the alternate valuation date. Answer: C

Explanation: C) Gift taxes are levied on the donor of a gift, not the recipient.

Page Ref.: I:1-8 through I:1-10

Objective: 3

52) Denzel earns $120,000 in 2012 through his job as a sales manager. What is his FICA tax?

A) $6,364

B) $8,566

C) $6,780

D) $9,180

Answer: A

Explanation: A) (110,100 × .042) + (120,000 × .0145) = $6,364

Page Ref.: I:1-11

Objective: 3

53) Martha is self-employed in 2012. Her business profits are $140,000. What is her self-employment tax?

A) $17,700

B) $15,510

C) $21,420

D) None of the above.

Answer: B

Explanation: B) (110,100 × .104) + (140,000 × .029) = $15,510

Page Ref.: I:1-11

Objective: 3

54) Which of the following is not one of Adam Smith's canons of taxation?

A) equity

B) convenience

C) certainty

D) paid by all citizens

Answer: D

Explanation: D) Smith's canons of taxation are equity, certainty, convenience and economy.

Page Ref.: I:1-11

Objective: 4

55) Horizontal equity means that

A) taxpayers with the same amount of income pay the same amount of tax.

B) taxpayers with larger amounts of income should pay more tax than taxpayer's with lower amounts of income.

C) all taxpayers should pay the same tax.

D) none of the above.

Answer: A

Explanation: A) Horizontal equity means that taxpayers with the same amount of income pay the same amount of tax.

Page Ref.: I:1-12

Objective: 4

56) Vertical equity means that

A) taxpayers with the same amount of income pay the same amount of tax.

B) taxpayers with larger amounts of income should pay more tax than taxpayer's with lower amounts of income.

C) all taxpayers should pay the same tax.

D) none of the above.

Answer: B

Explanation: B) Vertical equity means that taxpayers with larger amounts of income should pay more tax than taxpayer's with lower amounts of income.

Page Ref.: I:1-12

Objective: 4

57) Which of the following is not an objective of the federal income tax law?

A) Stimulate private investment.

B) Reduce employment.

C) Encourage research and development activities.

D) Prevent taxpayers from paying a higher percentage of their income in personal income taxes due to inflation.

Answer: B

Explanation: B) Reduction of unemployment is an objective.

Page Ref.: I:1-14 and I:1-15

Objective: 4

58) Which of the following is not a social objective of the tax law?

A) prohibition of a deduction for illegal bribes, fines and penalties

B) a deduction for charitable contributions

C) an exclusion for interest earned by large businesses

D) creation of tax-favored pension plans

Answer: C

Explanation: C) There is no exclusion for interest income earned by large businesses.

Page Ref.: I:1-15

Objective: 4

59) Which of the following is not a taxpaying entity?

A) Corporation

B) Partnership

C) Individual

D) All of the above are taxpayers.

Answer: B

Explanation: B) A partnership is a flow-through entity.

Page Ref.: I:1-17 through 23

Objective: 5

60) All of the following are classified as flow-through entities for tax purposes except

A) partnerships.

B) C corporations.

C) S corporations.

D) limited liability companies.

Answer: B

Explanation: B) A C corporation is a taxpaying entity.

Page Ref.: I:1-17

Objective: 5

61) Rocky and Charlie form RC Partnership as equal partners. Rocky contributes $100,000 into RC while Charlie contributes real estate with a fair market value of $100,000. During the current year, RC earned net income of $600,000. The partnership distributes $200,000 to each partner. The amount that Rocky should report on his individual tax return is

A) $0.

B) $100,000.

C) $200,000.

D) $300,000.

Answer: D

Explanation: D) Rocky must report 50% × $600,000 or $300,000, his share of partnership net income. The distribution of $200,000 is not taxable but rather nontaxable return of capital reducing Rocky's basis ($100,000 original investment + $300,000 share of income) by $200,000 to $200,000.

Page Ref.: I:1-21; Example I:1-18

Objective: 5

62) AB Partnership earns $500,000 in the current year. Partners A and B are equal partners who do not receive any distributions during the year. How much income does partner A report from the partnership?

A) $0

B) $250,000

C) $500,000

D) None of the above.

Answer: B

Explanation: B) $500,000 × .5 = $250,000

Page Ref.: I:1-21; Example I:1-18

Objective: 5

63) In an S corporation, shareholders

A) are taxed on their proportionate share of earnings.

B) are taxed only on dividends.

C) may allocate income among themselves in order to consider special contributions.

D) are only taxed on salaries.

Answer: A

Explanation: A) Similar to partners in a partnership, S corporation shareholders are taxed on their proportionate share of the income earned by the corporation, regardless of distribution payments.

Page Ref.: I:1-22

Objective: 5

64) All of the following statements are true except

A) the net income earned by a sole proprietorship is reported on the owner's individual income tax return.

B) the net income of an S corporation is subject to double taxation because it is taxed at the entity level and dividends paid from the S corporation to individual shareholders are also taxed.

C) the net income of C corporation is subject to double taxation because it is taxed at the entity level and dividends paid from the C corporation to individual shareholders is also taxed.

D) LLCs are generally taxed as partnerships.

Answer: B

Explanation: B) An S Corporation is a flow-through entity, not a taxable entity. The items of income/loss are allocated to each shareholder who pays tax on the items on his or her individual income tax return. Page Ref.: I:1-17 through 23

Objective: 5

65) Which of the following is not an advantage of a limited liability company (LLC)?

A) limited liability for all members of a LLC

B) ability to choose between taxation as a partnership or corporation

C) double taxation

D) All of the above are advantages of an LLC.

Answer: C

Explanation: C) A business operated as an LLC is a flow-through entity so it is not subject to double taxation.

Page Ref.: I:1-22 and I:1-23

Objective: 5

66) What is an important aspect of a limited liability partnership?

A) It is the same as a limited partnership where the general partner has unlimited liability.

B) A partner has unlimited liability arising from his or her own acts of negligence or misconduct or similar acts of any person under his or her direct supervision, but does not have unlimited liability in other matters.

C) All partners have limited liability regarding all partnership activities.

D) All partners have unlimited liability.

Answer: B

Explanation: B) A partner in an LLP remains responsible for his or her own actions, or those under his supervision, but is not liable for the actions of other partners.

Page Ref.: I:1-23

Objective: 5

67) The term "tax law" includes

A) Internal Revenue Code.

B) Treasury Regulations.

C) judicial decisions.

D) all of the above.

Answer: D

Explanation: D) The Code is a legislative source; the Regulations are an administrative source, and judicial decisions are judicial sources of tax law.

Page Ref.: I:1-24

Objective: 6

68) Which of the following serves as the highest authority for tax research, planning, and compliance activities?

A) Internal Revenue Code

B) Income Tax Regulations

C) Revenue Rulings

D) Revenue Procedures

Answer: A

Explanation: A)The Internal Revenue Code is the law passed by Congress. The other documents provide guidance in applying the law.

Page Ref.: I:1-24

Objective: 6

69) All of the following are executive (administrative) sources of tax law except

A) Internal Revenue Code.

B) Income Tax Regulations.

C) Revenue Rulings.

D) Revenue Procedures.

Answer: A

Explanation: A) The Internal Revenue Code is a legislative source.

Page Ref.: I:1-24 and Topic Review I:1-3

Objective: 6

70) Which of the following steps, related to a tax bill, occurs first?

A) signature or veto by the President of the United States

B) consideration by the Senate

C) consideration by the House Ways and Means Committee

D) consideration by the Joint Conference Committee

Answer: C

Explanation: C) Most tax legislation originates in the House of Representatives and is then referred to the House Ways and Means Committee.

Page Ref.: I:1-24

Objective: 7

71) A tax bill introduced in the House of Representatives is then

A) referred to the House Ways and Means Committee for hearings and approval.

B) referred to the full House for hearings.

C) forwarded to the Senate Finance Committee for consideration.

D) voted upon by the full House.

Answer: A

Explanation: A) Most tax legislation originates in the House of Representatives and is then referred to the House Ways and Means Committee.

Page Ref.: I:1-24

Objective: 7

72) When new tax legislation is being considered by Congress,

A) the tax bill will usually originate in the Senate.

B) different versions of the House and Senate bills are reconciled by the Speaker of the House and the President of the Senate.

C) different versions of the House and Senate bills are reconciled by a Joint Conference Committee.

D) after the President of the U.S. approves a tax bill, the Joint Conference Committee must then vote on passage of the bill.

Answer: C

Explanation: C) The Joint Conference Committee reconciles the House and Senate bills.

Page Ref.: I:1-25

Objective: 7

73) The Senate equivalent of the House Ways and Means Committee is the Senate

A) Joint Committee on Taxation.

B) Ways and Means Committee.

C) Finance Committee.

D) Joint Conference Committee.

Answer: C

Explanation: C) The Senate Finance Committee considers tax legislation.

Page Ref.: I:1-25

Objective: 7

74) When returns are processed, they are scored to determine their potential for yielding additional tax revenues. This program is called

A) Taxpayer Compliance Measurement Program.

B) Discriminant Function System.

C) Standard Audit Program.

D) Field Audit Program.

Answer: B

Page Ref.: I:1-27

Objective: 8

75) Which of the following individuals is most likely to be audited?

A) Lola has AGI of $35,000 from wages and uses the standard deduction.

B) Marvella has a $145,000 net loss from her unincorporated business (a horse farm). She also received $350,000 salary as a CEO of a corporation.

C) Melvin is retired and receives Social Security benefits.

D) Jerry is a school teacher with two children earning $45,000 a year. He also receives $200 in interest income on a bank account.

Answer: B

Explanation: B) Of those listed, the taxpayer with investments or trade or business expenses that produce significant losses, Marvella, is more likely to be audited.

Page Ref.: I:1-27

Objective: 8

76) Alan files his 2011 tax return on April 1, 2012. His return contains no misstatements or omissions of income. The statute of limitations for changes to the return expires

A) April 1, 2014.

B) April 15, 2015.

C) April 15, 2016.

D) The statute of limitations never expires.

Answer: B

Explanation: B) The three-year statute applies.

Page Ref.: I:1-28

Objective: 8

77) Peyton has adjusted gross income of $20,000,000 on his 2011 tax return, filed April 15, 2012. He accidentally failed to include $200,000 that he received for a television advertisement. How long does the IRS have to audit Peyton's federal tax return?

A) until April 15, 2014

B) until April 15, 2015

C) until April 15, 2018

D) The IRS can audit Peyton's return at any future date.

Answer: B

Explanation: B) The omission does not meet the 25% of reported income level, so the three-year statute still applies. Since the omission was accidental, the rules for fraud do not apply.

Page Ref.: I:1-28

Objective: 8

78) Latashia reports $100,000 of taxable income on her 2011 tax return, filed April 15, 2012. She omits $30,000 of income, but the error was not fraudulent. When does the statute of limitations for examining her tax return expire?

A) April 15, 2015

B) April 15, 2016

C) April 15, 2018

D) It never expires.

Answer: C

Explanation: C) The six-year statute applies since over 25% of income was omitted.

Page Ref.: I:1-28

Objective: 8

79) The IRS must pay interest on

A) all tax refunds.

B) tax refunds paid later than 30 days after the due date.

C) tax refunds paid later than 45 days after the due date.

D) The IRS never pays interest on tax refunds.

Answer: C

Page Ref.: I:1-28; Example I:1-27

Objective: 8

80) Kate files her tax return 36 days after the due date. When she files the return, she sends a check for $2,000 which is the balance of the tax owed by her. Kate's penalty for failure to file a return will be

A) 0.5% per month (or factor thereof) up to a maximum of 25%.

B) 5% per month (or factor thereof) up to a maximum of 25%.

C) 20% per month (or factor thereof).

D) none of the above.

Answer: B

Explanation: B) The penalty for failure to file is 5% per month up to 25%.

Page Ref.: I:1-28

Objective: 8

81) What are the correct monthly rates for calculating failure to file and failure to pay penalties?

Answer: C

Explanation: C) The penalty for failure to file is 5% per month up to 25%. The failure to pay penalty is.

0.5% per month up to 25%.

Page Ref.: I:1-28 and I:1-29

Objective: 8

82) Which is not a component of tax practice?

A) providing clients tax refund advance loans

B) tax research

C) tax planning and consulting

D) compliance

Answer: A

Page Ref.: I:1-29

Objective: 9

83) Larry and Ally are married and file a joint return. They are considering purchasing a personal residence that will generate two deductions: $10,000 in home mortgage interest and $8,000 in real estate taxes. Their marginal tax rate is 25%. What is the total tax savings if Larry and Ally purchase the residence?

Answer: ($10,000 + $8,000) × .25 = $4,500

Page Ref.: I:1-5; Example I:1-4

Objective: 2

84) Vincent makes the following gifts during 2012. Although he is married, none of the gifts are considered joint gifts with his wife. What are the total taxable gifts subject to the unified transfer tax? $15,000 cash gift to wife

Gift of automobile valued at $35,000 to his adult son

Gift of golf clubs valued at $5,000 to a friend

$10,000 contribution to church

Answer: $0 (no transfer tax on gift to spouse) + $22,000 ($35,000 gift to son - $13,000 exclusion per donee) + $0 ($5,000 - $13,000 exclusion per donee) + 0 (a contribution is not subject to the gift tax) = $22,000. Page Ref.: I:1-8; Example I:1-6

Objective: 3

85) Jeffery died in 2012 leaving a $6,000,000 gross estate. Six months after his death, the gross assets are valued at $6,100,000. In years prior to 2012 (but after 1976), Jeffery had made taxable gifts of $300,000. Of the $6,000,000 gross estate, one-half of the estate was transferred to his wife, administrative and funeral expenses were $100,000. Jeffery had debts of $200,000, and the remainder of the estate was transferred to his children.

a. What is the amount of Jeffery's taxable estate?

b. What is the tax base for computing Jeffery's estate?

c. What is the amount of estate tax owed if the tentative estate tax (before credits) is $1,730,800?

d. Alternatively, if six months after his death, the gross assets in Jeffery's estate declined in value to $2,000,000, can the administrator of Jeffery's estate elect the alternate valuation date?

d. The alternate valuation date (six months after the date of death) may be elected only if the aggregate value of the gross estate decreases during the six-month period following the date of death and the election results in a lower estate tax liability.

Page Ref.: I:1-10; Example I:1-8

Objective: 3

86) Mia is self-employed as a consultant. During 2012, Mia earned $180,000 in self-employment income. What is Mia's self-employment tax?

Answer:

.104 × $110,100 = $11,450

.029 × $180,000 = 5,220

Self-employment tax $16,670

Page Ref.: I:1-11

Objective: 4

87) Brad and Angie had the following income and deductions during 2012:

Salaries $110,000

Interest income 10,000

Itemized deduction 16,000

Taxes withheld during year 15,000

Calculate Brad and Angie's tax liability due or refund, assuming that they have 2 personal exemptions. They file a joint tax return.

Answer:

$110,000 + 10,000 - $16,000 - ($3,800 × 2) = $96,400 taxable income

Tax = $9,735 + .25(96,400 - 70,700) = $15,800

$15,800 - 15,000 taxes withheld = $800 taxes due

Page Ref.: I:1-17 and I:1-18

Objective: 5

88) Chris, a single taxpayer, had the following income and deductions during 2012?

Salary $55,000

Interest on bank accoun t300

Tax-exempt interest 200

Deduction for AGI 4,000

Itemized deductions 8,000

Taxes withheld 6,500

Calculate Chris's tax liability due or refund for 2012.

Answer:

Salary $55,000

Interest on bank account 300

Gross income 55,300

Deduction for AGI 4,000)

Adjusted gross income 51,300

Itemized deductions 8,000)

Personal exemption (3,800)

Taxable income $39,500

Tax $4,867.50 + .25(39,500 - 35,350) = $5,905

$6,500 taxes withheld - 5,905 = $595 tax refund

Page Ref.: I:1-17 and I:1-18

Objective: 5

89) During the current tax year, Frank Corporation generated gross income of $1,900,000 and had ordinary and necessary deductions of $1,400,000. What is the amount of Frank Corporation's corporate income tax for the year?

Answer: Taxable income is $1,900,000 - $1,400,000 = $500,000. The tax is $170,000 [$113,900 + .34 ($500,000 - 335,000)].

Page Ref.: I:1-19; Example I:1-14

Objective: 5

90) During the current tax year, Charlie Corporation generated gross income of $1,800,000 and had ordinary and necessary deductions of $1,300,000, resulting in taxable income of $500,000. If Charlie Corporation paid qualifying dividends of $200,000 to shareholders, all of whom are in the 25% marginal tax bracket, what is the total tax paid on both corporate income and the corporate dividends?

Answer: Taxable income is $1,800,000 - $1,300,000 = $500,000. Dividends are not tax deductible. The corporate income tax is $170,000 [$113,900 + .34 ($500,000 - 335,000)] and the shareholder tax on qualifying dividends is $30,000 ($200,000 × .15 maximum rate on qualifying dividends for taxpayers in 25% marginal tax bracket) for a total of $200,000.

Page Ref.: I:1-19 and I:1-20; Example I:1-15

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