ENG101: The main Reason for Selecting a Zener Diode as a Voltage Regulator is: Analogue Electronics Design Assignment, SUSS, Singapore

1)The main reason for selecting a Zener diode as a voltage regulator is

(A) The Zener diode has a constant voltage characteristic in the reverse breakdown region.

(B)  The Zener diode has constant voltage characteristics in the forward region.

(C)  The Zener diode can allow bidirectional current flow.

(D)The Zener diode can withstand reversed biasing.

2)  How do you describe the flow of diode current, id against the voltage when a diode is forward biased?

(A)       Id decreases with an increase in voltage.

(B)       Id increases exponentially with an increase in voltage.

(C)       Id remains the same for an increase in voltage.

(D)       Nothing happens.

3) For a Zener diode with Zener voltage, V_z connected across a variable voltage source, V_in, the output voltage, V_out  across the Zener when V_in < V_z  would be:

(A)       V_out  is more than V_z

(B) V_out is equal to V_z

(C) V_out is equal to V_in

(D)  V_out is equal to zero

4)  The output frequency of a full-wave rectifier for a given input signal of 60 Hz is

(A)       60 Hz

(B)       30 Hz

(C)       120 Hz

(D)       200 Hz

5)         Capacitive reactance_____________________ and inductive reactance __________________ with increase in frequency.

(A)       decreases, increases

(B)       increases, increases

(C)       decreases, decreases

(D)       remains same, remains same

Answer Q6 to Q10 in additional sheets provided.

6) Figure 1 shows a level shifter circuit. When a signal, v_i = 15sin(1000t) volts, is passed through the circuit, determine the peak voltage of v_o and its polarity. Assume the diode has an ideal characteristic.

7)  Calculate the total RMS (Root Mean Square) value for the source voltage,

v_s = – 5.0 + 7sin(2000t)?

Ans: Vp/root 2 = 2/root 2

= 1.414V

= 1.4V

8) Determine the turns ratio of a transformer with primary voltage Vp = 220 V and secondary voltage Vs = 22 V?

9) Find the Thevenin’s equivalent voltage for the circuit shown in Figure 2 as seen from across terminals A and B.

10. What is the DC voltage component contained in the rectified output of a rectifier circuit as shown in Figure 3? The AC source at the rectifier input is sinusoidal.

Ans: 2vm/3.142 = (2 x 15)/ 3.142 = 9.548V