Analog Electronics - Study Mode
[#206] An amplifier using an opamp with slew rate SR=1v/µsec has a gain of 40db.if this amplifier has to faithfully amplify sinusoidal signals from dc to 20 KHz without introducing any slew-rate induced distortion, then the input signal level must not exceed
Correct Answer
(C) 79.5 mV
[#207] Voltage Series (feedback also called series-shunt feedback) results in
Correct Answer
(C) Increase in input impedance & decreases in output impedance
Explanation
Solution: Option A: Increase in both input & output impedances is incorrect because voltage series (series-shunt) feedback does not increase both input and output impedances. While it does increase the input impedance, it decreases the output impedance. Therefore, this option does not correctly describe the effect of series-shunt feedback. Option B: Decreases in both input & output impedances is incorrect because voltage series feedback actually increases the input impedance and decreases the output impedance. Hence, this option is not applicable. Option C: Increase in input impedance & decreases in output impedance is correct because when voltage series feedback (also known as series-shunt feedback) is applied, it increases the input impedance and decreases the output impedance. This makes the amplifier more stable and improves its performance in certain applications. Option D: Decrease in input impedance & increase in output impedance is incorrect because voltage series feedback increases the input impedance, not decreases it, and it also decreases the output impedance, not increases it. Therefore, this option does not describe the behavior of voltage series feedback. Conclusion: The correct answer is Option C: Increase in input impedance & decreases in output impedance because voltage series (series-shunt) feedback increases the input impedance while decreasing the output impedance, improving amplifier performance.
[#208] MOSFET can be used as a
Correct Answer
(B) Voltage controlled capacitor
[#209] An amplifier using BJT has two identical stages each having a lower cut-off (3 dB) frequency of 64 Hz due to coupling capacitor. The emitter bypass capacitor also provides a lower cut-off (3 dB) frequency due to emitter degeneration alone of 64 Hz. The lower (3 dB) frequency of the overall amplifier is nearly
Correct Answer
(A) 100 Hz
[#210] What would be the output of the following circuit, if a positive going unipolar pulse with an amplitude greater than V ref , is applied at the input?
Correct Answer
(C) V o will go high and remain high