1) The output transformer used in a power amplifier is a _____________ transformer? a. 1:1 ratio b. Step-up c. Step-down d. None of the above
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2) The pulsating d.c. applied to power amplifier causes________________? a. Burning of transistor b. Hum in the circuit c. Excessive forward voltage d. None of the above
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3) If the gain versus frequency curve of a transistor amplifier is not flat, then there is distortion ? a. Amplitude b. Intermodulation c. Frequency d. None of the above
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4) If the power rating of a transistor is 1W and collector current is 100mA, then maximum allowable collector voltage is________________? a. 1V b. 100V c. 20V d. 10V
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5) What will be the collector efficiency of a power amplifier having zero signal power dissipation of 5 watts and a.c. power output of 2 watts ? a. 20% b. 80% c. 40% d. 50%
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6) The driver stage usually employs_________________? a. Class A power amplifier b. Push-pull amplifier c. Class C amplifier d. None of the above
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7) The output signal voltage and current of a power amplifier are 5V and 200 mA; the values being r.m.s. What is the power output ? a. 1 W b. 2 W c. 4 W d. None of the above
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8) The push-pull circuit must use ______________ operation? a. Class A b. Class C c. Class B d. Class AB
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9) What turn ratio (Np/Ns) of transformer is required to match 4 O speaker to a transistor having an output impedance of 8000 O ? a. 2 b. 7 c. 3 d. None of the above
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10) For the same a.c. power output as above, what should be the minimum power rating of transistor for class B operation? a. 10 W b. 4 W c. 8 W d. None of the above
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