109年 - 109 國立臺北大學_日間學士班曁進修學士班轉學生招生考試試題_通訊工程學系日間學士班3年級：電子電路#147355

1. (10%) Find the equivalent resistance of the terminal a-b in Fig 1.

Fig. 1

Fig. 2

2. (10%) Use \( V{1} \) and \( V{2} \) to express the voltage \( V_{0} \) of the op amp circuit in Fig. 2.

3. (Total \( 10\% \) ) For the RL circuit in Fig. 3, assume \( Vs = V_{m}cos\omega t \)

(a) Obtain the transfer function \( V{0} / V{s} \) (5%).
(b) Sketch its frequency response for the magnitude in dB scale. Mark the magnitude and the frequency of the half power point. (5%)

Fig. 3

Fig. 4

4. (10%) Plot the input/output characteristic of the circuit shown in Fig. 4 using the ideal model.

5. (10%) A p-type semiconductor has the doping level \( N{A} = 1.5 \times 10^{16} / \mathrm{cm}^{3} \). Assume that \( n{i} = 2 \times 10^{10} / \mathrm{cm}^{3} \). Find the hole and electron concentrations (you must specify what value is hole concentration and what value is electron concentration).

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國立臺北大學 109 學年度日間學士班暨進修學士班轉學生招生考試試題

學制系級：通訊工程學系日間學士班 3 年級

科 目：電子電路

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☐可 ☑不可使用計算機

6. (10%) Express the voltage gain of the circuit in Fig. 5. Assume small signal parameters are gm and rtt and assume VA=∞. Assume the emitter current and the collector current are approximately equal.

Fig. 5

Fig. 6

7. (10%) Determine the voltage gain of a follower driven by a finite source impedance of Rs in Fig. 6. Assume small signal parameters are \( g{\mathrm{m}} \), \( r{\mathrm{tt}} \), and \( \beta \) and assume \( V_{\mathrm{A}} = \infty \).

8. (10%) Determine the value of W/L in Fig. 7 that places M1 at the edge of saturation. \( \mu{\mathrm{n}}C{\mathrm{ox}} = 50\mu A / V^2, V_{\mathrm{th}} = 0.5\mathrm{V} \) and \( \lambda = 0 \)

Fig. 7

Fig. 8

Fig. 9

9. (10%) Determine the voltage gain of the circuit shown in Fig. 8 if \( \lambda > 0 \). Assume small signal parameters are \( g{\mathrm{m}} \) and \( r{\mathrm{0}} \).

10. (10%) Compute the voltage gain of the circuit shown in Fig. 9, if \( \lambda = 0 \) for M1 and \( \lambda > 0 \) for M2. Assume small signal parameters are \( g{\mathrm{m}} \) and \( r{\mathrm{o}} \).