Prentice hall's federal taxation test bank chapter 9

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

Chapter C9 Partnership Formation and Operation

1) Formation of a partnership requires legal documentation filed with the Secretary of State.

Answer: FALSE

Page Ref.: C:9-2

Objective: 1

2) A partner's basis for his partnership interest can be negative.

Answer: FALSE

Page Ref.: C:9-5

Objective: 1

3) The holding period of a partnership interest acquired in exchange for a contributed capital asset begins on the date the partner transfers the asset to the partnership.

Answer: FALSE

Page Ref.: C:9-8

Objective: 3

4) A partnership cannot make charitable contributions.

Answer: FALSE

Page Ref.: C:9-16

Objective: 2

5) ABC Partnership distributes $12,000 to partner Al. Al's distributive share of partnership income is $20,000. Al is taxed on $20,000.

Answer: TRUE

Page Ref.: C:9-17

Objective: 6

6) A partner's "distributive share" is the partner's share of any assets distributed by the partnership. Answer: FALSE

Page Ref.: C:9-17

Objective: 6

7) A partner's share of nonrecourse debt increases that partner's share of basis.

Answer: TRUE

Page Ref.: C:9-22

Objective: 7

8) A partner's basis for his or her partnership interest is increased by his share of the partnership's tax-exempt income.

Answer: TRUE

Page Ref.: C:9-24

Objective: 7

9) Limited partners must consider the at-risk, basis, and passive loss limitations when determining the amount of their deductible loss.

Answer: TRUE

Page Ref.: C:9-26 and C:9-27

Objective: 8

10) No gain is recognized on the sale of property between a partnership and a more-than-50% partner. Answer: FALSE

Page Ref.: C:9-28

Objective: 8

11) Guaranteed payments are always ordinary income to the recipient.

Answer: TRUE

Page Ref.: C:9-28

Objective: 9

12) A partnership must file Form 1065 only if its income exceeds $1,000.

Answer: FALSE

Page Ref.: C:9-32

Objective: 12

13) Identify which of the following statements is true.

A) Formation of a partnership requires legal documentation.

B) An individual engaged in the active conduct of a business must elect not to be taxed as a partnership.

C) A partnership exists as long as there are at least two individuals or entities engaged in the active conduct of a trade or business or a financial operation, and the business is not a trust or a corporation.

D) All of the above are false.

Answer: C

Page Ref.: C:9-2

Objective: 1

14) The definition of a partnership does not include

A) a syndicate.

B) a group.

C) a pool.

D) All of the above are included.

Answer: D

Page Ref.: C:9-2

Objective: 1

15) Identify which of the following statements is true.

A) All of the partners in a limited partnership have limited liability.

B) A limited partnership must have at least two general partners.

C) A limited partnership cannot have a corporate general partner.

D) All of the above are false.

Answer: D

Page Ref.: C:9-3

Objective: 1

16) Which of the following is false?

A) A large partnership must not be a service partnership.

B) A large partnership must have fewer than 100 partners.

C) A large partnership must not be engaged in commodity trading.

D) A large partnership is subject to a different system of audits.

Answer: B

Page Ref.: C:9-4

Objective: 1

17) Electing large partnership rules differ from other partnership rules in all of the following areas except

A) partnership income reporting.

B) partnership termination.

C) partnership audits.

D) All of the above are large partnership rule differences.

Answer: D

Page Ref.: C:9-4

Objective: 1

18) On the first day of the partnership's tax year, Karen purchases a 50% interest in a general partnership for $30,000 cash and she materially participates in the operation of the partnership for the entire year. The partnership has $40,000 in recourse liabilities when Karen enters the partnership. Partners share the economic risk of loss from recourse liabilities in the same way they share partnership losses. There is no minimum gain related to the nonrecourse liability. During the year, the partnership incurs a $120,000 loss and a $20,000 increase in liabilities. How much of the loss can Karen report on her tax return for the current year?

A) $30,000

B) $40,000

C) $50,000

D) $60,000

Answer: D

The loss is deductible only to the extent of Karen's at-risk basis, or $50,000.

Page Ref.: C:9-5; Example C:9-3

Objective: 1

A) Distribution of partnership income in the form of cash to partners is generally tax-free to the partners and the partnership.

B) When partners receive cash distributions from the partnership, they pay taxes on those distributions.

C) If money distributions exceed the partner's basis in the partnership interest, the partner would have to recognize gain on the distribution from the partnership. Such gain is usually an ordinary gain.

D) All of the above are true.

Answer: A

Page Ref.: C:9-5

Objective: 1

20) George pays $10,000 for a 20% interest in a general partnership, which has recourse liabilities of $20,000. The partners share the economic risk of loss from recourse liabilities in the same way they share partnership losses. George's basis in his partnership interest is

A) $10,000.

B) $12,000.

C) $14,000.

D) $30,000.

Answer: C

Page Ref.: C:9-5; Example C:9-1

Objective: 1

21) On January 1, Helmut pays $2,000 for a 10% capital, profits, and loss interest in a partnership, which has recourse liabilities of $20,000. The partners share economic risk of loss from recourse liabilities in the same way they share partnership losses. In the same year, the partnership incurs losses of $6,000 and the recourse liabilities increase by $5,000. Helmut and the partnership use a calendar tax year-end. Helmut's basis at year-end is

A) $1,500.

B) $2,000.

C) $3,500.

D) $3,900.

Answer: D

Page Ref.: C:9-5; Example C:9-2

Objective: 1

A) A contribution of services for a partnership interest is a tax-free transaction.

B) For federal income tax purposes, formation of a partnership is governed by Sec. 721.

C) When a partnership assumes a liability on property contributed by a partner, the only effect on the contributing partner's basis in his or her partnership interest is that his or her basis will be increased by the amount of the liability assumed by the other partners.

D) All of the above are false.

Answer: B

Page Ref.: C:9-6 and C:9-7

Objective: 2

23) Yong contributes a machine having an adjusted basis of $20,000 and an FMV of $25,000 for a 10% partnership interest. Yong had taken $10,000 of depreciation prior to the contribution. The partnership has no liabilities. As a result of the contribution, Yong must recognize

A) no gain or loss.

B) a $5,000 Sec. 1245 gain.

C) a $5,000 capital gain.

D) $10,000 ordinary income.

Answer: A

Explanation: A) No gain or loss is recognized at the time of the contribution.

Page Ref.: C:9-6 and C:9-7

Objective: 3

24) Identify which of the following statements is true.

A) A partner's relief of debt is treated as if the partner receives a cash distribution.

B) When a partnership assumes any liabilities of the transferor, the transferor has an increase in the basis of his or her partnership interest.

C) Gain recognized by a contributing partner because of the assumption of liabilities by the partnership increases the partnership's basis in the contributed property.

D) All of the above are false.

Answer: A

Page Ref.: C:9-6 and C:9-7

Objective: 3

25) For a 20% interest in partnership capital, profits, and losses, Kasi contributes a machine having a basis of $30,000 and an FMV of $40,000. The partnership also assumes a $24,000 recourse liability secured by the machine. The partnership has $6,000 in recourse liabilities immediately preceding Kasi's contributions. Partners share the economic risk of loss from recourse liabilities in the same way they share partnership losses. Kasi's basis in the partnership interest is

A) $10,800.

B) $12,000.

C) $13,200.

D) $30,000.

Answer: B

Page Ref.: C:9-7; Example C:9-6

Objective: 3

26) For a 30% interest in partnership capital, profits, and losses, Carol contributes a machine with a basis of $40,000 and an FMV of $80,000. The partnership assumes a $70,000 recourse liability on the machine.

At the time of the contribution, the partnership had recourse liabilities of $10,000. Partners share the economic risk of loss from recourse liabilities in the same way they share partnership losses. Following the contribution, Carol has

A) a capital loss due to the contribution of $6,000 and a zero basis in the partnership interest.

B) a capital gain due to the contribution of $6,000 and a zero basis in the partnership interest.

C) a $34,000 basis in the partnership interest and no gain or loss.

D) a $43,000 basis in the partnership interest and no gain or loss.

Answer: B

Page Ref.: C:9-7; Example C:9-7

Objective: 3

27) Stella acquired a 25% interest in the STUV Partnership by contributing land having an adjusted basis of $32,000 and a fair market value of $100,000. The land was subject to a $48,000 mortgage, which was assumed by STUV. No other liabilities existed at the time of contribution. What is Stella's basis in her partnership interest?

A) $0

B) $32,000

C) $52,000

D) $64,000

Answer: A

Page Ref.: C:9-7; Example C:9-7

Objective: 3

28) David contributes investment land with a basis of $24,000 and an FMV of $40,000 to a partnership for

a 10% interest in partnership capital, profits, and losses. The land is subject to a $30,000 recourse liability, which is assumed by the partnership. The partnership has other recourse liabilities of $18,000. Partners share the economic risk of loss from recourse liabilities in the same way they share partnership losses. David must recognize a

A) $3,000 capital gain.

B) $3,000 capital loss.

C) $1,200 capital gain.

D) $1,200 capital loss.

Answer: C

Page Ref.: C:9-7; Example C:9-7

Objective: 3

29) Rashad contributes a machine having a basis of $30,000 and an FMV of $25,000 to a partnership in exchange for a 20% interest in partnership capital, profits, and losses. Prior to the contribution, the partnership had recourse liabilities of $20,000. The partnership assumes a $20,000 recourse liability that is owed by Rashad on the machine. Partners share the economic risk of loss from recourse liabilities in the same way they share partnership losses. Rashad's basis in his partnership interest is

A) $11,000.

B) $18,000.

C) $22,000.

D) $34,000.

Answer: B

Page Ref.: C:9-7

Objective: 3

30) Albert contributes a Sec. 1231 asset to a partnership on June 1 of this year in exchange for a 10% partnership interest. He had purchased the asset on March 1, 2002. His holding period for the partnership interest begins

A) March 1, 2002.

B) March 2, 2002.

C) June 1 of the current year.

D) June 2 of the current year.

Answer: A

Page Ref.: C:9-8

Objective: 3

31) Mario contributes inventory to a partnership on August 1 of this year in exchange for a 20% partnership interest. Mario had purchased the inventory on July 2 of last year. His holding period for the partnership interest begins

A) July 2 of last year.

B) July 3 of last year.

C) August 1 of the current year.

D) August 2 of the current year.

Answer: D

Page Ref.: C:9-8

Objective: 3

32) Allen contributed land, which was being held for sale to Allen's customers, to a partnership in exchange for a 20% interest. The partnership uses the land in its business for three years and then sells the property. When the property was contributed, it had a basis in Allen's hands of $500,000 and an FMV of $600,000. The partnership sells the land for $700,000. The gain reported by the partnership is

A) $100,000 of ordinary income and $100,000 of Sec. 1231 gain.

B) $100,000 of Sec. 1231 gain and $100,000 of capital gain.

C) $200,000 of ordinary income.

D) $200,000 of Sec. 1231 gain.

Answer: C

Land, which is held as inventory by Allen, retains its character as inventory in the hands of the partnership for five years after the contribution.

Page Ref.: C:9-8 and C:9-9

Objective: 3

33) Bao had investment land that he purchased in 1990 for $80,000. Two years ago, when the land was contributed to a partnership, the FMV was $50,000. The land is inventory in the hands of the partnership. The partnership then sells the land in the current year for $46,000. The partnership's recognized loss is

A) a $34,000 capital loss.

B) a $34,000 ordinary loss.

C) a $30,000 capital loss and a $4,000 ordinary loss.

D) a $4,000 capital loss and a $30,000 ordinary loss.

Answer: C

Explanation: C) The $30,000 precontribution loss retains its character as a capital loss, but the loss accrued since the contribution date is ordinary loss.

Page Ref.: C:9-9

Objective: 3

34) Karl arranges financing for a limited partnership to purchase real estate in exchange for a 50% interest in partnership profits. Two weeks later, Karl sells the profits interest for $30,000. In this tax year, Karl must recognize

A) no gain or loss.

B) a $30,000 short-term capital gain.

C) a $30,000 ordinary income.

D) a $30,000 Sec. 1231 gain.

Answer: C

Page Ref.: C:9-10; Example C:9-12

Objective: 3

A) The contribution of Sec. 1245 property to a partnership triggers recognition of ordinary income by the contributor at the time of the transfer.

B) A partner may not recognize ordinary income when receiving a capital and profits interest in a partnership in exchange for services.

C) When a partnership interest is given to a partner in exchange for services, the partnership can deduct or capitalize the FMV of the services, depending on the nature of the services.

D) All of the above are false.

Answer: C

Page Ref.: C:9-11

Objective: 3

36) Ali, a contractor, builds an office building for a construction partnership in exchange for a capital and profits interest in the partnership worth $500,000. Which of the following statements is correct?

A) Ali recognizes $500,000 of ordinary income and the partnership can deduct $500,000 in the current year.

B) Ali recognizes no income and the partnership can deduct nothing in the current year.

C) Ali recognizes $500,000 ordinary income and the partnership deducts the $500,000 over the building's MACRS recovery period as a depreciation expense.

D) Ali recognizes ordinary income in the current year in an amount equal to the depreciation deduction the partnership claims this year for the $500,000 capitalized amount.

Answer: C

Page Ref.: C:9-11; Example C:9-14

Objective: 3

37) Bob, Kara, and Mark are partners in the BKM Partnership. Bob is a 40% partner and has a June 30 tax year-end. Kara owns a 40% interest in the partnership and has a September 30 tax year-end, and Mark owns the remaining 20% interest and has an October 31 tax year-end. The partnership does not have a natural business year. What is the required tax year-end for the partnership (if no Sec. 444 election is made)?

A) June 30

B) September 30

C) October 31

D) December 31

Answer: A

Explanation: A) The least aggregate deferral for the alternative tax year-ends is:

The smallest of the four alternatives is June 30.

Page Ref.: C:9-12 through C:9-14; Example C:9-17

Objective: 4

A) The Fisher Partnership is owned equally by four individual partners. Two of the partners have fiscal years ending March 31 and two partners have fiscal years ending June 30. The partnership has a natural business year. The partnership must adopt a calendar year for tax reporting purposes unless a Sec. 444 election is made.

B) Partnerships make most of the tax elections for the partnership rather than the partners.

C) A partner can elect the depreciation method to be applied to the partner's share of the partnership's depreciable assets.

D) All of the above are false.

Answer: B

Page Ref.: C:9-15

Objective: 4

39) Identify which of the following statements is true.

A) A partnership cannot have an NOL carryback or carryforward.

B) A partnership cannot make charitable contributions.

C) Dividends received by a partnership from a domestic corporation are included in the partnership's ordinary income.

D) All of the above are false.

Answer: A

Page Ref.: C:9-16

Objective: 2

40) Identify which of the following statements is true.

A) Tax-exempt interest received by a partnership is taxable to the partners if distributed.

B) Partnership gains and losses from two different casualty and theft occurrences in one year are passed through to the partners as two separate items.

C) The amount and character of any gains/losses is determined at the partnership level.

D) All of the above are false.

Answer: C

Page Ref.: C:9-16

Objective: 2

41) Matt and Joel are equal partners in the MJ Partnership. For the current year ended December 31, the partnership has book income of $80,000, which includes the following deductions: (1) guaranteed payments (salaries) to partners: Matt, $35,000; and Joel, $25,000; and (2) charitable contributions, $6,000. The book income amount does not include any sales of capital assets or Sec. 1231 assets or any tax-exempt income. Based on the above information, what amount should be reported as ordinary income on the partnership return?

A) $60,000

B) $80,000

C) $86,000

D) $140,000

Answer: C

Page Ref.: C:9-17

Objective: 2

42) Identify which of the following statements is true.

A) A partner's distributive share includes the full amount of partnership ordinary income, which she must report on her tax return plus her share of separately stated taxable and tax-exempt items.

B) Sam has a 20% interest in partnership capital and profits but a 40% interest in partnership losses. The partnership has no special allocations or precontribution gains or losses. In a year in which the partnership reports ordinary income of $100,000 and a capital loss of $30,000, Sam's distributive share is $20,000 ordinary income and $12,000 capital loss.

C) The partner's distributive share is the partner's share of any assets distributed by the partnership.

D) All of the above are false.

Answer: A

Page Ref.: C:9-17

Objective: 6

43) In computing the ordinary income of a partnership, a deduction is allowed for

A) net Sec. 1231 losses.

B) bad debts.

C) foreign income taxes paid.

D) charitable contributions.

Answer: B

Page Ref.: C:9-17

Objective: 6

44) Identify which of the following statements is true.

A) The Hunter Partnership has a net long-term capital gain of $4,000 and a net short-term capital loss of $1,000 for the current tax year. The gain and loss will be netted and the partners will include their proportionate share of the $3,000 net long-term capital gain on their return.

B) The Right Partnership sells a delivery truck and recognizes a gain of $2,000, which represents depreciation recaptured under Sec. 1245. The $2,000 gain will retain its identity as a separately stated item.

C) For tax purposes, the partnership takes a carryover basis in the contributed property that references the contributing partner's basis.

D) All of the above are false.

Answer: C

Page Ref.: C:9-18 and C:9-19

Objective: 5

45) On January 2 of the current year, Calloway and Taylor contribute cash equally to form the CT Partnership. Calloway and Taylor share profits and losses in a ratio of 75% and 25%, respectively. The partnership's ordinary income for the year was $40,000. Calloway received a distribution of $5,000 during the year. What is Calloway's share of taxable income for the year?

A) $5,000

B) $10,000

C) $20,000

D) $30,000

Answer: D

Page Ref.: C:9-18

Objective: 6

46) The XYZ Partnership reports the following operating results for the current year:

Tai has a 20% profits interest and a 25% loss interest in the XYZ Partnership. His distributive share of ordinary income is

A) $6,800.

B) $8,500.

C) $10,000.

D) $12,500.

Answer: D

Explanation: D) Since the partnership has a net loss [($40,000) + ($16,000) + $50,000 = ($6,000)] for the year, Tai's distributive share of the $50,000 of ordinary income is calculated using the 25% loss interest.

Page Ref.: C:9-18; Example C:9-20

Objective: 6

47) Latoya owns a 10% interest in the ABC Partnership from January 1 through June 30 (the 181st day of the tax year) of the current year (a non-leap year). On July 1, Latoya buys an additional 10% interest in the partnership. The XYZ Partnership's ordinary income is $109,500 and it is earned evenly throughout the year. Latoya's distributive share of the ordinary income is

A) $16,380.

B) $16,425.

C) $16,470.

D) $21,900.

Answer: C

Page Ref.: C:9-18; Example C:9-21

Objective: 6

48) On December 1, Antonio, a member of a three-person partnership, purchases investment securities from the partnership for their $37,000 FMV. All partners share profits and losses equally. The securities were acquired by the partnership for $25,000 cash in March of the current year. What amount and character of gain will Antonio recognize because of this transaction?

A) $0 gain

B) $4,000 ordinary income

C) $4,000 short-term capital gain

D) $12,000 ordinary income

Answer: C

Explanation: C) ($37,000 - $25,000) × 1/3 = $4,000 short-term capital gain from the sale of securities.

Page Ref.: C:9-18

Objective: 6

49) Meg and Abby are equal partners in the AM Partnership, which earns $40,000 ordinary income, $6,000 long-term capital gain (LTCG), and $2,000 Sec. 1231 loss during the current year. What is the amount and character of income that must be reported on Abby's tax return for this year's partnership operations?

A) $20,000 ordinary income, $3,000 LTCG, $1,000 Sec. 1231 loss

B) $19,000 ordinary income, $3,000 LTCG

C) $23,000 ordinary income, $1,000 Sec. 1231 loss

D) $22,000 ordinary income

Answer: A

Page Ref.: C:9-18

Objective: 6

50) On December 31 of last year, Alex and Jackson become equal partners in the AJ Partnership with assets having a tax basis and FMV of $120,000. The partnership, which deals in securities, had no liabilities at the end of last year. In January of this year, Franklin contributes his investment securities with an FMV of $60,000 (purchased two years ago at a cost of $45,000) to become an equal partner in the new AJF Partnership. The securities, which are inventory to the partnership, are sold on December 15 of the current year for $90,000. What amount and character of gain from the sale of these securities should be allocated to Franklin?

A) $10,000 ordinary income

B) $15,000 capital gain and $10,000 ordinary income

C) $25,000 capital gain

D) $25,000 ordinary income

Answer: D

There is no special provision to preserve the capital gain character for Jackson, so the entire gain is ordinary income.

Page Ref.: C:9-18 and C:9-19

Objective: 6

51) At the formation of the BD Partnership, Betty contributes land with a basis of $10,000 and an FMV of $30,000 and Dick contributes cash of $30,000. Betty and Dick share profits and losses equally. When the land is sold two years later for $50,000, Betty must recognize a gain of

A) $10,000.

B) $20,000.

C) $30,000.

D) $40,000.

Answer: C

Page Ref.: C:9-19

Objective: 6

52) Identify which of the following statements is false.

A) Jean and Blossom form an equal partnership. Jean contributes $10,000 cash and Blossom contributes property with a $10,000 FMV and a $5,000 basis. When the partnership sells the property contributed by Blossom for $10,000 shortly after the formation, Blossom must include the $5,000 gain in her income.

B) In order to shift income/loss between partners, there must be substantial economic effect.

C) The BB Partnership wants to make a special allocation of $10,000 of long-term capital gain to Bob and a special allocation of $10,000 of ordinary income to Briana. This allocation will have a substantial economic effect.

D) Partners must make up negative balances in their capital accounts upon liquidation of the partnership. Answer: C

Page Ref.: C:9-19

Objective: 6

53) William and Irene each contribute $20,000 cash to the WI Partnership on January 1 of last year. William and Irene share profits and losses equally. Last year, the partnership reported tax-exempt interest income of $4,000. This year, each partner receives $1,000 of the tax-exempt interest income in a cash distribution. There are no partnership liabilities and no other income, loss, contributions, or distributions during both years. William's basis in the partnership interest following these transactions is

A) $19,000.

B) $20,000.

C) $21,000.

D) $22,000.

Answer: C

Page Ref.: C:9-21 through C:9-23

Objective: 7

54) Miguel has a 50% interest in partnership capital, profits, and losses. The basis for his partnership interest is $50,000. The partners share the economic risk of loss from recourse liabilities in the same way they share partnership losses. Miguel receives a distribution of land that has an FMV of $40,000 and an adjusted basis of $30,000. The land is subject to a $15,000 liability, which Miguel assumes. His basis in the partnership interest following the land distribution is

A) $12,500.

B) $20,000.

C) $27,500.

D) $35,000.

Answer: C

Page Ref.: C:9-22; Example C:9-26

Objective: 7

55) Identify which of the following statements is true.

A) A general partner's share of recourse debt is based on his or her economic risk of loss, and his or her share of nonrecourse debt is predominantly based on his or her share of partnership profits.

B) A partner's basis for his or her partnership interest is increased by his or her share of the partnership's tax-exempt income.

C) If all tax-exempt interest income is distributed when received by a partnership, the partners' bases are the same after the distribution as they were before the tax-exempt interest was received by the partnership.

D) All of the above are true.

Answer: D

Page Ref.: C:9-22 and C:9-23

Objective: 7

56) Identify which of the following statements is true.

A) Although a partner's basis in the partnership cannot go below zero, a partner's book capital account (equity) may be negative.

B) Tom purchased for cash a 40% capital, profits, and loss interest in the TP General Partnership. His $140,000 basis in his partnership interest includes his $45,000 share of recourse debt and his $30,000 of nonrecourse debt (that is not qualified nonrecourse real estate financing). His at-risk basis cannot be more than $65,000.

C) Terri is a limited partner in the STU Partnership, which manufactures children's toys. Because the partnership is actively involved in a trade or business, Terri's income from the partnership is classified as active income for the passive activity loss rules.

D) All of the above are false.

Answer: A

Page Ref.: C:9-25

Objective: 2

57) Identify which of the following statements is true.

A) When adjusting a partner's basis in a partnership interest, the negative basis adjustments are made prior to the positive basis adjustments.

B) Martin and Carlos formed an equal partnership to which Martin contributed $10,000 cash and Carlos contributed a building worth $10,000 with a basis of $2,000. In the first year of operation, the partnership suffered a $10,000 ordinary loss. Martin and Carlos can each deduct a $5,000 loss on their personal tax returns.

C) Any distributive share of a loss that cannot be deducted by a partner because of the Sec. 704(d) basis loss limitation is permanently lost.

D) All of the above are false.

Answer: D

Page Ref.: C:9-24 and C:9-25

Objective: 2

58) Stan had a basis in his partnership interest at the beginning of last year of $30,000. There was no change in partnership liabilities during the year. His share of the partnership's ordinary loss last year was $40,000 and the partnership had no separately stated items. This year, Stan has a distributive share of ordinary income of $30,000. The taxable income from the partnership reported on Stan's personal income tax return this year (ignoring the at-risk and passive activity loss limitations) is

A) $10,000 ordinary loss.

B) $20,000 ordinary income.

C) $30,000 ordinary income.

D) $40,000 ordinary income.

Answer: B

Explanation: B) $30,000 - $10,000 loss carryover = $20,000.

Page Ref.: C:9-25

Objective: 6

59) A partnership has one general partner, Allen, who materially participates in the business. Allen had a $30,000 distributive share of ordinary losses for this year and the partnership had no separately stated gains or losses. There are no changes in liabilities during this year and there are no additional contributions or distributions. At the beginning of this year, the Sec. 705 basis was $40,000 and the at-risk basis was $15,000. The basis on December 31 of this year based on the above information is

A) $10,000.

B) $15,000.

C) $25,000.

D) $40,000.

Answer: A

Explanation: A) $40,000 - $30,000 = $10,000

Page Ref.: C:9-25

Objective: 7

60) Martin is a limited partner in a card shop. At the end of the partnership's tax year, Martin's basis in the partnership interest is $25,000 ($5,000 cash investment plus a $20,000 share of nonqualified nonrecourse financing). Martin's distributive share of partnership losses for the tax year is $33,000. Martin has $30,000 of passive income this year from other activities. How much of the $33,000 partnership loss can be used by Martin in the year of the loss?

A) $5,000

B) $25,000

C) $30,000

D) $33,000

Answer: A

Explanation: A) Martin's total basis under Sec. 704(d) is $25,000. However, his $5,000 cash investment is the only amount for which he is at risk under the at-risk rules and sets the limit on his loss deduction, since he has $30,000 of passive income.

Page Ref.: C:9-26; Example C:9-32

Objective: 8

61) David purchased a 10% capital and profits interest in a partnership this year. He does not participate in the partnership's business. David has no passive income in the current year. His distributive share of the partnership's loss is $40,000 for this year. David's Sec. 705 basis in the partnership is $32,000 and his at-risk basis is $16,000 at the end of the current year. How much of the loss can David deduct on his tax return?

A) $0

B) $16,000

C) $32,000

D) $40,000

Answer: A

Explanation: A) David's passive loss limitation is zero and is the controlling factor.

Page Ref.: C:9-27; Example C:9-33

Objective: 8

62) Jangyoun sells investment land having a $30,000 basis to a partnership in which he has a 60% partnership interest. The partnership pays $26,000 (FMV) for the land. Later, the partnership sells the investment land to a nonpartner for $31,000. On the sale of the land, the partnership must recognize a

A) $0 gain or loss.

B) $1,000 capital gain.

C) $4,000 capital gain and $1,000 Sec. 1231 gain.

D) $5,000 capital gain.

Answer: B

Jangyoun realized a $4,000 loss ($26,000 - $30,000) on the sale of the land to the partnership. The $4,000 loss is disallowed in the year of Jangyoun's sale, but can offset the partnership's realized gain, thus reducing it to a $1,000 recognized gain. The gain is capital because the land was held for investment purposes by the partnership.

Page Ref.: C:9-28; Example C:9-36

Objective: 9

63) Identify which of the following statements is true.

A) A partner who performs services for a partnership is usually not considered an employee of the partnership.

B) It may be necessary for the partnership to capitalize a partner's guaranteed payment.

C) Guaranteed payments are ordinary income to the recipient.

D) All of the above are true.

Answer: D

Page Ref.: C:9-28 and C:9-29

Objective: 9

64) When computing the partnership's ordinary income, a deduction is allowed for

A) contributions to charitable organizations.

B) net operating losses.

C) net short-term capital losses.

D) guaranteed payments to partners.

Answer: D

Page Ref.: C:9-29

Objective: 9

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