用戶【pianista2202】點評問題和點評內容

【評論主題】30 在下圖中,開關閉合瞬間,N2線圈之感應電流所產生的磁通方向為何?(A)向下(B)向上(C)向右(D)向左

【評論內容】

上面產生的磁通方向向下,那下面的不是會產生一個向上反抗磁通?

【評論主題】【題組】49 What does the author of this article suggest that vegans do to gain all necessary nutrition?(

【評論內容】

Vegan diets tend to be higher in dietary fiber, vitamin C, vitamin E, iron, and phytochemicals, and lower in calories, saturated fat, cholesterol, vitamin D, calcium, zinc, and vitamin B12.

此處雖提到higher in dietary fiber,但只是作者平鋪直述素食的飲食內容。

Because uncontaminated plant foods do not provide vitamin B12 (which is produced by micro-organisms such as bacteria),vegans should eat foods fortified with B12 or take a daily supplement.

這裡作者 建議 加強(fortified)攝取B12

【評論主題】38 驅動電壓源 vS=4 sin(2×104t+30°) 伏特的 RLC 串聯電路中,當流過 R=1 kΩ 的電流振幅大小為 4 mA時,此電路之諧振頻率 ω0為多少(rad/s)?(A)8 k (

【評論內容】

算電流的時候電壓不用換成有效值嗎

這題應該是藉由電流可以直接由電阻和電壓算出

不用考慮電容和電感,所以判斷為諧振吧

【評論主題】24.如【圖7】所示,若Vcc=12V、Rc=l k 、β=58,電晶體基射級順向導通電壓為0.7 V ’集射 極飽和電壓為0.4V,則可使電路得到最大不失真輸出訊號之電阻RB值約為多少? (A) 9

【評論內容】

不失真所以不能工作在飽和區,所以IC(sat)≧βIB 

然後再用IB算RB,這樣算出來RB是56.5剛好是正解的一半,

有人知道為甚麼嗎?

【評論主題】24.如【圖7】所示,若Vcc=12V、Rc=l k 、β=58,電晶體基射級順向導通電壓為0.7 V ’集射 極飽和電壓為0.4V,則可使電路得到最大不失真輸出訊號之電阻RB值約為多少? (A) 9

【評論內容】

不失真所以不能工作在飽和區,所以IC(sat)≧βIB 

然後再用IB算RB,這樣算出來RB是56.5剛好是正解的一半,

有人知道為甚麼嗎?

【評論主題】30 在下圖中,開關閉合瞬間,N2線圈之感應電流所產生的磁通方向為何?(A)向下(B)向上(C)向右(D)向左

【評論內容】

上面產生的磁通方向向下,那下面的不是會產生一個向上反抗磁通?

【評論主題】32 如圖之差動對電路,電晶體之 β = 100,ro→∞,RC = 4 kΩ,I = 2 mA,VCC = -VEE=10 V,取 VBE(on) = 0.7 V,VCE(sat) = 0.3 V,

【評論內容】

感謝解答~

所以只需要算其中一個電晶體的AV就是Ad了?

【評論主題】【題組】49 What does the author of this article suggest that vegans do to gain all necessary nutrition?(

【評論內容】

Vegan diets tend to be higher in dietary fiber, vitamin C, vitamin E, iron, and phytochemicals, and lower in calories, saturated fat, cholesterol, vitamin D, calcium, zinc, and vitamin B12.

此處雖提到higher in dietary fiber,但只是作者平鋪直述素食的飲食內容。

Because uncontaminated plant foods do not provide vitamin B12 (which is produced by micro-organisms such as bacteria),vegans should eat foods fortified with B12 or take a daily supplement.

這裡作者 建議 加強(fortified)攝取B12

【評論主題】38 驅動電壓源 vS=4 sin(2×104t+30°) 伏特的 RLC 串聯電路中,當流過 R=1 kΩ 的電流振幅大小為 4 mA時,此電路之諧振頻率 ω0為多少(rad/s)?(A)8 k (

【評論內容】

算電流的時候電壓不用換成有效值嗎

這題應該是藉由電流可以直接由電阻和電壓算出

不用考慮電容和電感,所以判斷為諧振吧

【評論主題】5.如【圖2】之電源供應器,在輸出端可測得Eout應為: (A)21.21Vdc (B)10.6Vdc (C) 9.54 Vdc (D) 7.5 Vdc

【評論內容】

看懂了,這題是中間抽頭,故二次側電壓為15Vm

又全波整流Vdc=2Vm/pi。

但是題目也沒說二次側的電壓是Vrms還是Vm,有辦法判斷嗎?

【評論主題】37.RC相移振盪器,若以四節RC作為回授網路,則每節應產生幾度之相移?(A)30。 (B)45°(C)90。 (D) 180。

【評論內容】

每級相移60 三級180

為何四級 不是每級相移45

【評論主題】24.如【圖7】所示,若Vcc=12V、Rc=l k 、β=58,電晶體基射級順向導通電壓為0.7 V ’集射 極飽和電壓為0.4V,則可使電路得到最大不失真輸出訊號之電阻RB值約為多少? (A) 9

【評論內容】

不失真所以不能工作在飽和區,所以IC(sat)≧βIB 

然後再用IB算RB,這樣算出來RB是56.5剛好是正解的一半,

有人知道為甚麼嗎?

【評論主題】14.在一RC耦合電路中,<3須取大值,其原因為何?(A)消散高功率(B)防止低頻衰減(C)產生較佳之偏壓穩定(D)級與級間之直流可順利通過

【評論內容】

在一RC耦合電路中,C須取最大值,其原因為何?

A 消散高功率

B 防止低頻衰減

C 產生較佳之偏壓穩定

D 級與級間之直流可順利通過

【評論主題】24 圖示雙極性接面電晶體(BJT)電路,電晶體 β = 100,VBE = 0.7 V,當電路處最佳工作點,則電阻RB約為若干 kΩ? (A)115(B)230(C)460(D)575

【評論內容】

請問假如圖中數值有變

那最佳工作點應該設為多少

要以什麼為依據呢

【評論主題】【題組】50 Which of the following is true about the new policy in terms of job assignment?(A)All positio

【評論內容】

Dempsey and Panetta said the new policy reflects the realities of female soldiers’ changing roles over the past decade. More than 280,000 women have been deployed to Iraq and Afghanistan, and more than 150 have died. They’ve patrolled dangerous areas as military police, served as machine gunners atop military vehicles, searched Iraqi and Afghan women for weapons, and more. New jobs will be opened gradually to women throughout the next few years. The entire process is expected to be complete by January 1, 2016.過去十年間該新政策的結果如橘色字所示...

【評論主題】【題組】49 What did the CBS poll show?(A)Americans generally agree with the new policy.(B)More than half

【評論內容】

Recent polls by CBS News and the Pew Research Center, for example, showed that two thirds (66 percent) of Americans support ending the ban.

2/3的人民支持