GROUP STUDY - OPAMPS AND ICS QUESTIONNAIRE.doc

GROUP STUDY - OP AMPS AMPS AND IC’S DIGITAL DIGITAL ELECTRONICS ANSWER KEY

1. An amplifier amplifier basically basically construct constructed ed from two transistor transistors s and whose output output is proportional proportional to the differe difference nce between between the voltages applied to its two inputs. differ eren enti tial al ampl amplif ifie ierr b. casc cascod ode e ampli amplifi fier er c. compl complem emen entar tary y ampl amplif ifie ierr d.qu d.quas asii-co comp mple leme ment ntary ary ampl amplif ifie ier  r  a. diff 2. It is a very high-gain high-gain different differential ial amplifier amplifier with with very high input input impedance impedance and very low output output impedance. impedance. b. op-amp c. differential amp d. complementary amp a. par-amp 3. What are are the possible possible applicati applications ons of operational operational amplifier amplifiers s op-amps!" op-amps!" a. ac and dc-amplifiers c. oscillators and signal conditioning age-lleve evel det detec ecttors an and co comparato ators d. al all of of the the above b. voltage#. An operation operational al amplifier amplifier must have have at least how many many usable usable terminal terminals" s" a. 3 terminals b. $ terminals c. % terminals d. 1# terminals $. Ideally& Ideally& op-amps have have infinite infinite input input resistance resistance and ''''''' '''''''' ' output resista resistance. nce. b. (ero c. variable d. a highly stabili(ed a. Infinite ). When the same signal signal is applie applied d to both invertin inverting g and non-inv non-inverti erting ng input termina terminals ls of an ideal op-amp& op-amp& the output output voltage would be a. (ero *! + b. ,+A c. /+A d. offset voltage 0. he operat operating ing mode mode of an op-amp op-amp&& when both input inputs s are tied togethe togetherr or when when the input signal signal is common common to both inputs. a. differential mode b. reection mode c. double-ended mode d. common mode %. When one input input of the op-amp op-amp is connect connected ed to ground ground and the other other is to the signal signal source& source& its its operation operation is called called single le-e -end nded ed outp output ut b. doub double le-e -end nded ed outp output ut c. sing single le-e -end nded ed inpu inputt d. doub double le-e -end nded ed inpu inputt a. sing . If op-amps op-amps are operate operated d in differen differential tial mode& mode& its gain gain is technic technically ally termed termed as a. common-mode di differential ga gain b. di differential ga gain c. op open-loop ga gain d. cl closed-loop ga gain 1*. An operation operational al amplifi amplifier er has a commoncommon-mode mode voltage voltage gain of 1* and a differ differenti entialal-mode mode voltage voltage gain of 2*&***& 2*&***& calculate its common-mode reection ratio 455!. a. 2** b. 2&*** c. 2*&*** d. 2**&*** 11. 11. he non-inverting non-inverting and inverting inverting inputs of an op-amp have an input voltage of 1.$ m+ and 1.* m+& respectiv respectively ely.. If the op-amp has a common-mode voltage gain of 1* and a differential-mode gain of 1*&***& what is its output voltage" b. $.*12$ m+ c. $.*12$ + d. 2$.*12$ + a. $.* + 12. What is the ma6imum ma6imum output output voltage voltage swing of an op-amp" op-amp" a. ,+ to to -+ -+ supply vo voltage! b. ,+ ,+A to /+ /+A c. ,7 ,7+ to to -7 -7+ d. de depends on on th the in input si signal 13. he 8A0#1 op-amp op-amp has a 455 of *d9 and a differential differential-mode -mode voltage voltage amplification amplification of 2**&***.What 2**&***.What is the opamp:s common-mode voltage gain" b. )32.#* c. ).32# d. *.1$% a. 31&)22.00% 1#. he current current needed at the the input of an op-amp to operate operate it normally normally bias current b. in input offset current c. in input th threshold cu current d. in input holding cu current a. input bi 1$. he reason why a slight differenc difference e between the input bias current current occurs in op-amps is due to the unsymmetrical unsymmetrical circuit component parameters. his unsymmetrical condition also produces a difference in input voltage called what" a. dri drift volta oltage ge b. di differ fferen enti tial al volta oltage ge c. input nput off offset set vol volta tage ge d. inpu inputt thr thres esho hold ld volta oltag ge 1). It is ;nown through e6periment e6periment that the input bias currents currents at the non-inverting non-inverting I9,! and inverting inverting I9-! inputs of a certain op-amp is 1** nA and %* nA& respectively. ( increased in frequency d. a gain reduction by a factor of 2* per 1* >( increased in frequency 2*. A reduction reduction of op-amp:s op-amp:s voltage voltage gain gain by a factor factor of two each each time time the frequency frequency doubles. doubles. a. 2 d9=octave b. 2 d9=decade c. ) d9=octave d. ) d9=decade 21. ?reque ?requency ncy at at which which the the voltag voltage e gain gain of op-amp op-amp reduc reduces es to unity unity.. a. unity-gain fr frequency b. cu cutoff frequency c. ba bandwidth po point d. un unity-gain ba bandwidth product 22. he ma6imu ma6imum m output output voltag voltage e rate rate of of chang change e of an op-amp op-amp.. b. ma6imum voltage swing c. differential rate d. slew rate a. rise time 23. What is is the ma6imum ma6imum signal signal freque frequency ncy that that can be used in an op-amp op-amp having having a specifi specified ed slew rate rate of *.$ +=8sec +=8sec" "

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What must must be the slew slew rate rate of an op-amp to be used used in order order to provide provide an undisto undistorte rted d output output voltage voltage of .1* + ac a frequency of 1**&*** rad=sec" b. *.$ +=8sec c. 1.* +=8sec d. ).2% +=8sec a. *.1 +=8sec When an an op-amp op-amp is used as as a comparator comparator&& the the output output voltage voltage would would be ,+A ,+A  if  a. +, @ +b. +- @ +, c. +-  +, d. +- and +, are both (ero wo wo comparato comparators rs using using op-amps& op-amps& configu configured red such such that it can detect voltag voltage e levels levels within within a certai certain n range of values values rather than simply comparing whether a voltage is above or below a certain reference. a. analog comp omparator ator b. re regenerativ tive co comparato ator c. parallel comp omparator d. wi window dow compar parator  What gain gain is signi significa ficant nt when when an op-am op-amp p is used used as a volt voltage age compa comparat rator" or" mon gain c. differential closed loop oop gain ain d. close osed loop gain a. open-loop gain b. common he feedb feedbac; ac; eleme element nt of a diffe differen rentia tiator tor const construc ructed ted from from op-amp op-amp is a. a resistor b. an inductor c. a capacitor d. an 5 networ; An activ active e integra integrator tor uses uses an op-am op-amp& p& what what is its its feedbac feedbac; ; elemen element" t" b. capacitor c. inductor d. 5 networ; a. 5esistor he voltag voltage e gain gain of of an op-amp op-amp voltage voltage followe follower. r. a. Bnity b. 5f=5i c. 1 , 5f=5i d. depends on the type of op-amp alculate alculate the closedclosed-loop loop voltage voltage gain gain of an inverting inverting amplifie amplifierr having having a feedbac; feedbac; and an input input resistance resistance of of 1** ;C and 1* ;C& respectively. a. 1* b. 11 c. 1** d. 11* A unityunity-gai gain n summing summing amplifi amplifier er has three three inputs& inputs& +1  1.* m+& +2 +2  1.$ m+& and and +3  2.$ m+& m+& calcul calculate ate the total total output voltage. b. 3.$ m+ c. #.* m+ d. $.* m+ a. 2.$ m+ ircui ircuits ts that that produces produces alte alterna rnating ting or or pulsati pulsating ng curren currentt or voltag voltage. e. a. artley d. Bltraudion a. Eierce What determi determines nes the reso resonant nant frequenc frequency y of a cryst crystal" al" a. e6ternal components c. the temperature of the crystal the si(e si(e and and thi thic; c;nes ness s of the the cry cryst stal al mat mater eria iall d. the the herm hermit itic ic seal seal b. the ype ype of oscillator oscillator whose whose frequenc frequency y is depende dependent nt on the the charge charge and and discharge discharge of of 5 networ networ;s. ;s. a. >art artley osc oscillator b. olpitts oscillator c. 5ela6 ela6a ation osc oscillato ator d. Flystron oscillator  A micr microw owav ave e osci oscill llat ator  or  b. o olpitts oscillator c. 5ela6ation oscillator d. Fl Flystron oscillator   a. >artley oscillator A self-e6 self-e6cited cited oscillat oscillator or in which which the tan; is is divided divided into input input and feedbac; feedbac; portions portions by a capacitive capacitive voltage voltage divider divider.. b. o olpitts oscillator c. 5ela6ation oscillator d. Fl Flystron oscillator   a. >artley capacitor A circuit circuit usuall usually y containing containing two two transistors transistors or tubes tubes in an 5-cou 5-coupled pled amplifier amplifier&& the two two active devices devices switc switch h each other alternately on and off. a. 4ultivibrator b. ignal generator c. Gscillator d. hyristor   A multivibrat multivibrator or that that generates generates one output output pulse for each each input input trigger trigger pulse. b. astable c. bistable d. tristate a. 4onostable 4onos 4onosta tabl ble e multi multivi vibr brato atorr is also also ;now ;nown n as a. one shot b. single shot c. direct shot d. one shot or single shot What determi determines nes the the pulse pulse time time in a monos monostabl table e multivi multivibrat brator" or" c.capacitor combinations a. resistor combinations b. inductor combinations d. resistor and capacitor combinations ?lip-fl ?lip-flop op is actual actually ly a '''' ''''''' ''' multiv multivibr ibrator ator.. b. bistable c. astable d. unstable a. 4onostable ons onsid ider ered ed as a freefree-ru runn nnin ing g multi multivi vibr brato ator  r  a. 4onostable b. bistable c. astable d. unstable It ta;es an op-amp 22 us to to change its output from /1$ + to to ,1$ +. +. as only one usable threshold b. Bses hysteresis to speed up response c. lamps the input positively d.