# Basic Electronics 3

First Year Engineering Common to all Branches: Basic Electronics 3

Subject: Basic Electronics 3

Part 3: List for questions and answers of Basic Electronics

Q1. An operational amplifier is in saturation if:
a) Its input impedance becomes very small
b) The theoretical output voltage is less than the positive supply voltage
c) Its output impedance becomes very large
d) The theoretical output voltage is greater than the positive supply voltage

Q2. If Ad=3500 and Acm=0.35,the CMRR is_________
a) 1225
b) 10000
c) 80dB
d) both b and c

Q3. Where the input terminals are floating ,the amplifier is usually designed to operate as a ————— amplifier
a) non-inverting
b) differential
c) inverting
d) summing

Q4. When an Op-Amp is used as a non-inverting amplifier, the input signal is fed into the_________ input and the ________ input is grounded through a resistor
a) Non-inverting, inverting
b) Inverting, non-inverting
c) Feedback, slew rate
d) All of the above

Q5. CMRR is a large number, which may alternately be quoted in ———–
a) Decibels
b) Volt
c) Ampere

Q6. A certain op-amp has bias currents of 50uA and 49.3uA.the input offset current Is______
a) 700nA
b) 99.3uA
c) 49.7uA
d) none of these

Q7. In a scaling adder, the input resistors are
a) All of the same value
b) All of different values
c) Each proportional to the weight of its inputs
d) Related by the factor of two

Q8. What characteristics would characterize an ideal operational amplifier?
a) An infinite voltage gain, zero input resistance and zero output resistance
b) An infinite voltage gain, an infinite input resistance and an infinite output resistance
c) An infinite voltage gain, an infinite input resistance and zero output resistance
d) An infinite voltage gain, zero input resistance and an infinite output resistance

Q9. What would be a typical value for the unity-gain bandwidth of a 741 operational amplifier?
a) 104
b) 105
c) 106
d) 107

Q10. In an integrator, the feedback element is a
a) Resistor
b) Capacitor
c) Zenar Diode
d) Voltage Dividor

Q11. If the voltage gain for each input of a summing amplifier with
a) 4.7 Kilo-Ohms feedback resistor is unity, the input resistors must have a value of
b) 4.7 Kilo-Ohms
c) 4.7 Kilo-Ohms divided by the number of inputs
d) 4.7 Kilo-Ohms times the number of inputs

Q12. A differential amplifier has
a) one input
b) two inputs
c) three inputs
d) none of the above

Q13. The output of a particular op-amp increases 8V in 12usec.The slew rate is____
a) 96v/us
b) 0.67v/us
c) 1.5v/us
d) none of these

Q14. In differential amplifiers, the transistors are
a) of different characteristics
b) one N-P-N and other P-N-P
c) unmatched
d) matched

Q15. A differential amplifier is used in op-amp circuits because of its
a) high input impedance
b) low input impedance
c) low CMRR
d) high CMRR

Q16. A common mode signal is applied to
a) the inverting input
b) the non-inverting input
c) both the inputs
d) none of the above

Q17. If the two input terminals of a diff-amp are grounded, then
a) an output offset voltage may exist
b) the ac output voltage is zero
c) the base currents are equal
d) the collector currents are equal

Q18. If a differential amplifier having an open loop gain of 80 dB is fed with 2mV dc at its non inverting input and 1.9 mV dc at the inverting input ,then the output will be
a) 1 V dc
b) -1V dc
c) zero as op-amp does not amplify dc
d) none of the above

Q19. If open loop gain of op-amp is 200000 and common mode gain of 0.3 the CMRR is ______
a) 116.47dB
b) 100dB
c) 120dB
d) 48dB

Q20. The input offset current of a diff-amp is the
a) average of the two base currents
b) difference of the two base currents
c) average of the two collector currents
d) difference of the two collector currents

Part 3: List for questions and answers of Basic Electronics