Floyd -- A-21

Q: Every known element has A: a unique type of atom Q: An atom consist of A: one nucleus and one or more electrons; protons, electrons and neutrons Q: The nucleus of an atom is made up of A: protons and neutrons Q: The atomic number of silicon is A: 14 Q: The atomic number of germanium is A: 32 Q: The valence shell in a silicon atom has the letter designation of A: M Q: Valence electrons are A: in the most distant orbit from the nucleus Q: A positive ion is formed when A: a valence electron breaks away from the atom Q: The most widely used semiconductive material in electronic devices is A: silicon Q: The energy bond in which free electrons exist is the A: conduction bond Q: Electron-hole pairs are produced by A: thermal energy Q: Recombination is when A: an electron falls into a hole Q: In a semiconductor crystal, the atoms are held together by A: the interaction of valence electrons, forces of attraction and covalent bonds Q: Each atom in a silicon crystal has A: eight valence electrons, four of its own and four shared Q: The current in a semiconductor is produced by A: both electrons and holes Q: In an intrinsic semiconductor A: the free electrons are thermally produced and there are as many electrons as there are holes Q: The difference between insulator and a semiconductor is A: a wider energy gap between the valence bond and the conductive bond, the number of free electrons, the atomic structure Q: The process of adding an impurity to an intrinsic semiconductor is called A: doping Q: A trivalent impurity is added to silicon to create A: p-type semiconductor Q: The purpose of a pentavalent impurity is to A: increase the number of free electrons Q: The majority carriers in an n-type semiconductor are A: conduction electrons Q: Holes in an n-type semiconductor are A: minority carriers that are thermally produced Q: A pn junction is formed by A: the boundary of a p-type and an n-type material Q: The depletion region is created by A: ionization, diffusion and recombination Q: The depletion region consists of A: positive and negative ions and no majority carriers Q: The term bias means A: a dc voltage is applied to control the operation of the device Q: To forward bias a pn junction A: an external voltage is applied that is positive at the anode and negative at the cathode or an external voltage is applied that is positive at the p region and negative at the n region Q: When a pn junction is forward bias, A: the current is produced by both holes and electrons Q: Although current is blocked in reverse bias, A: there is very small current due to minority carriers Q: For a silicon diode, the value of the forward bias voltage is typically A: greater than 0.7 V Q: When forward-biased, a diode A: conducts current Q: When a voltmeter is placed across a forward-biased diode, it will read a voltage approximately equal to A: the diode barrier potential Q: A silicon diode is in series with a 1 kO resistor and a 5 V battery. If the anode is connected to the positive battery terminal, the cathode voltage with respect to the negative battery terminal is A: 4.3 V Q: The positive lead of the ohmmeter is connected to the anode of a diode and the negative lead is connected to the cathode. The diode is A: forward-biased Q: The average value of the half-wave rectified voltage with a peak value of 200 V A: 63.7 V Q: When a 60 Hz sinusoidal voltage is applied to the input of a half-wave rectifier, the output frequency is A: 60 Hz Q: The peak value of the input to half-wave rectifier is 10 V. The approximate peak value of the output is A: 9.3 V Q: When a 60 Hz sinusoidal voltage is applied to the input of a full-wave rectifier the output frequency is A: 120 Hz Q: The total secondary voltage in a center-tapped full-wave rectifier is 125 V rms. Neglecting the diode drop, the rms voltage output is A: 62.5 V Vp(out) = 0.5 Vp(in) Q: When the peak output voltage is 100 V, the PIV for each diode in a center-tapped full-wave rectifier is (neglecting the diode drop) A: 200 V PIV >/= 2 Vp Q: When the rms output voltage of a full-wave bridge rectifier is 20 V, the peak inverse voltage across the diode is (neglecting the diode drop) A: 28.3 V PIV = Vp Q: The ideal dc output voltage of a capacitor filter is equal to A: the peak value of the rectified voltage Q: A certain power supply filter produces an output with a ripple of 100 mV peak-to-peak and a dc value of 20 V. The ripple factor is A: 0.005 r = V r(p-p) / V (dc) r = 100 mV / 20 V r = 0.005 Q: A 60 V peak full-wave rectified voltage is applied to a capacitor filter. If f = 120 Hz, RL = 10 kO and C = 10 F, the ripple voltage is A: 5.0 V V r(p-p) = Vm / (fRLC) = 60 / (120 x 10k x 10) = 5 V Q: If the load resistance of a capacitor-filtered full-wave rectifier is reduced, the ripple voltages A: increases V r(p-p) = Vm / (fRLC) Q: A 10 V(p-p) sinusoidal voltage is applied across a silicon diode and series resistor. The maximum voltage across the diode is A: 4.3 V Q: If the input voltage to a tripler has an rms value of 12 V, the dc output voltage is approximately A: 32.4 V Vdc = 2\2 V rms / t or use V rms = 1.11 V dc Q: If one of the diodes in a full wave bridge rectifier opens, the output is A: a half-wave rectified signal Q: What happens to one of the diodes in a full-wave bridge rectifier if it is observed that the output has a 60 Hz ripple A: there is an open diode Q: The cathode of a Zener diode in a voltage regulator is normally A: more positive than the anode Q: If a Zener diode has a Zener voltage of 3.6 V, it operates in A: Zener breakdown Q: For a certain 12 V Zener diode, a 10 mA change in Zener current produces a 0.1 V change in Zener voltage. The Zener impedance for this current change is A: 10 O Zz = A Vz / A Iz = 0.1 V / 10 mA = 10 O Q: The data sheet for a particular Zener gives Vz = 10 V and Izt = 500 mA, Zz for this condition is A: 20 O Zz = Vz / Iz = 10 V / 500 mA = 20 O Q: Line regulation is determined by A: change in output voltage and input voltage Line Reg. = AVout / AVin x 100% Q: Load regulation is determined by A: changes in load current and output voltage Load Reg. = (Vnl Vfl)/Vfl x 100% Therefore, load regulation is the same as voltage regulation. Q: A no-load condition means that A: the load has infinite resistance or the load has zero resistance Q: A varactor diode exhibits A: a variable capacitance that depends on the reverse voltage Q: An LED A: emits light when forward-biased Q: Compared with a visible red LED, an infrared LED A: produces light with longer wavelengths Q: The internal resistance of a photodiode A: decreases with light intensity when reversed -biased Q: A diode that has a negative resistance characteristics is the A: tunnel diode Q: An infrared LED is optically coupled to a photodiode. When the LED is turned off, the reading on an ammeter in series with a reversed-biased photodiode will A: decrease Q: In order for a system to function properly, the various types of circuits that make up the system must A: properly biased, properly connected, and properly interfaced Q: The three terminals of a bipolar junction transistor are called A: base, emitter and collector Q: In a pnp transistor, the p regions are A: emitter and collector Q: For operation as an amplifier, the base of an npn transistor must be A: positive with respect to the emitter Q: The emitter current must be A: greater than the base current and the collector current Q: The |dc of a transistor is its A: current gain Q: If Ic is 50 times larger than Ib, then |dc is A: 50 Q: If |dc is 100, the value of odc is A: 0.99 Q: The approximate voltage across the forward-biased base-emitter junction of a silicon BJT is A: 0.7 V Q: The bias condition for a transistor to be used as a linear amplifier is A: forward-reverse Q: If the output of a transistor amplifier is 5 V rms and the input is 100 mV rms, the voltage gain is A: 50 Q: When operated in cutoff and saturation, the transistor acts like A: switch Q: In cut0ff, Vce is A: maximum and equal to Vcc Q: In saturation, Vce is A: minimum Q: To saturate a BJT A: Ib > Ic(sat) / |dc Q: Once in saturation, a further increase in base current will A: not affect the collector current Q: If the base-emitter junction is open, the collector voltage is A: Vcc Q: The maximum value of a collector current in a biased transistor is A: Ic(sat) Q: Ideally, a dc load line is straight line drawn on the collector characteristic curves between A: Vce(cut-off) and Ic(sat) Q: If a sinusoidal voltage is applied to the base of a biased npn transistor and the resulting sinusoidal collector voltage is clipped near zero volts, the transistor is A: being driven into saturation and operating nonlinearly Q: the dc beta h(FE) for a given type of transistor A: varies with temperature and from device to device Q: The disadvantage of base bias is that A: it is too beta dependent Q: Emitter bias is A: essentially dependent of |dc and provide a stable bias point Q: In an emitter bias circuit R(B) = 2.7 kO and V(EE) = 15 V. The emitter current is A: cannot be determined unless Vcc is given Q: The input resistance at the base of the biased transistor depends mainly on A: |dc and R(E) Q: In a certain voltage divider biased npn transistor, V(B) is 2.95 V. The dc emitter voltage is approximately A: 2.25 V V(B) = V(BE) + V(EE) V(EE) = 2.95 V 0.7 V = 2.25 V Q: Voltage divider bias can be essentially independent of __ A: |dc Q: Collector feedback is based on the principle of A: negative feedback Q: In a voltage-divider biased npn transistor, if the upper voltage-divider resistor (the one connected to the Vcc) opens A: the transistor goes into cutoff Q: In a voltage-divider biased npn transistor, if the lower voltage-divider resistor (the one connected to the ground) opens A: the transistor may be driven into saturation Q: A small-signal amplifier A: uses only a small portion of its load line Q: The parameter h(FE) corresponds to A: |dc Q: If the dc emitter current in a certain transistor amplifier is 3 mA, the approximate value of re is A: 8.33 O re = 25 mV / I(E) = 25 mV / 3 mA = 8.33 O Q: For a common-collector amplifier, R(E) = 100 O, re = 10 O, and |ac = 150. The input resistance at the base is A: 16.5 kO Rin(base) = |[R(E) + re] = 150(100 + 10) = 16.5 k O Q: A certain common emitter amplifier has a voltage gain of 100. If the emitter bypass capacitor is removed, A: the voltage gain will decrease with bypass capacitor Av = Rc / re without bypass capacitor Av = Rc / [re + R(E)] Q: For a common-emitter amplifier, Rc = 1 kO, R(E) = 390O, re = 15 O, and |ac = 15075. Assuming that R(E) is completely bypassed at the operating frequency, the voltage gain is A: 66.7 Av = Rc / re = 1 k / 15 = 66.7 Q: In a certain common-collector circuit, the current gain is 50. The power gain is approximately A: 50 x Av or just 50 Q: In a darlington configuration, each transistor has an ac beta of 125. If R(E) is 560 O, the input resistance is A: 8.75 MO Zi = R(B) //[ri + |(D)R(E)] Zi ~ |(D)R(E) ~ (125)2 x 560 O ~ 8.75 MO Q: The input resistance of a common-base amplifier is A: very low Q: A CE amplifier is driving a 10kO load. If Rc = 2.2 kO and re = 10O, the voltage gain is approximately A: 180 Av = -(Rc//ro) / re = -(10 k // 2.2 k) / 10 = 180.33 Q: Each stage of a four-stage amplifier has voltage gain of 15, the overall gain is A: 50,625 Av(t) = 15(15)(15)(15) = 50,625 Q: When the Q-point of an inverting class A amplifier is closer to saturation than cutoff and the input is gradually increased, clipping on the output will first appear on A: the negative peaks Q: The saturation value of ac collector current for an amplifier with an ac collector resistance of 3 kO and Q-point values of Icq = 2 mA and Vceq = 3 V is A: 3 mA Vce = Vcc IcRc; Vcc = 9 V Ic(sat) = Vcc / Rc = 3mA Q: If re = 18O and Rc = 500 O in a class A amplifier, the large voltage gain is A: 27.8 Av = Rc / re = 500 / 18 = 27.78 Q: A class A amplifier is biased with a centered Q-point at Vceq = 5 V and Iceq = 10 mA. The maximum output power is A: 25 mW Po(max) = 0.5 VceqIcq = 0.5 x 5 x 10 m = 25 mW Q: A certain class A amplifier has a current gain of 75 and a voltage gain of 50. The power gain is A: 3750 Ap = AvAi = 50(75) = 3750 Q: The transistors in class B are biased A: right at cutoff Q: The emitters of certain class B push-pull amplifier have a Q-point value of 10 V. If Rc is 50 O, the value Ic(sat) is A: 0.2 A Ic(sat) = 10 / 50 = 0.2 A Q: The power dissipation of a class C amplifier is normally A: very low Q: The JFET is A: a unipolar device and also a voltage-controlled device Q: The channel of a JFET is between the A: drain and source Q: A JFET always operates with A: the gate-to-source pn junction reversed-biased Q: For Vgs = 0 V, the drain current becomes constant when Vds exceeds A: Vp or pinch-off voltage Q: The constant current region of an FET lies between A: pinch-off and breakdown Q: Idss is A: the maximum possible current Q: Drain current in the constant-current region increases when A: the gate-to-source bias voltage decreases Q: In a certain FET circuit, Vgs = o V, Vdd = 15 V, Idss = 15 mA, and Rd = 470 O. If Rd is decreased to 330 O, Idss is A: 15 mA (it is unaffected) Q: At cutoff, the JFET channel is A: completely closed by the depletion region Q: A certain JFET data sheet gives Vgs(off) = -4 V. The pinch-off voltage, Vp, is A: +4 V Q: If a JFET has a pinch-off voltage of a positive value, it is a __ - channel A: N Q: For a certain JFET, Igss = 10 nA at Vgs = 10 V. The input resistance is A: 1000 MO Rin = Vgs / Igs = 10 / 10 nA = 1000 MO Q: For a certain p-channel JFET, Vgs(off) = 8 V. The value of Vgs for an approximate midpoint bias is A: 2.43 V Q: A MOSFET differs from a JFET mainly because A: the JFET has a pn junction Q: A certain D-MOSFET is biased at Vgs = 0 V. Its data sheet specifies Idss = 20 mA and Vgs(off) = -5 V. The value of the drain current is A: 20 mA Id = Idss [1 Vgs / Vgs(off) ]2 Q: An n-channel D-MOSFET with a positive Vgs is operating in A: the enhancement mode Q: A certain p-channel E-MOSFET has a Vgs(th) = -2 V. If Vgs = 0 V, the drain current is A: 0 A Q: A TMOSFET is a special type A: E-MOSFET Q: In a common source amplifier, the output voltage is A: 1800 out of phase with the input and it is taken at the drain Q: In a certain common source (CS) amplifier, Vds is 3.2 Vrms and Vgs = 280 mV rms. The voltage gain is A: 11.4 Av = Vgs / Vds = 3.2 / 280 m = 11.4 Q: In a certain CS amplifier, Rd = 1 kO, Rs = 500O, Vdd = 10 V, and gm = 4500 S. if the source resistor is completely bypassed, the voltage gain is A: 4.5 Av =gmRd = 4500 x 1k = 4.5 Q: Ideally, the equivalent circuit of a FET contains A: a current source between drain and source terminals Q: The value of the current source in the ideal equivalent circuit of an FET is dependent on the A: transconductance and gate-to-source voltage Q: A certain common source amplifier has a voltage gain of 10. If the source bypass capacitor is removed, A: the voltage gain will decrease Q: A CS amplifier has a load resistance of 10 k O and Rd = 820 O. If gm = 5 mS and Vin = 500 mV, the output signal voltage is A: 1.89 V Av = Vo / Vi Av = gm (Rd // ro) / 2 Q: If the load resistance in a CS amplifier is removed, the output voltage will A: increase Q: A certain common drain (CD) amplifier with Rs = 1 kO has a transconductance of 6000 S. The voltage gain is A: 0.86 Av = gmRs / (1 + gmRs) Q: The data sheet for the transistor used in a CD amplifier specifies Igss = 5 nA at Vgs = 10 V. If the resistor from the gate to ground, Rg is 50 M O, the total input resistance is approximately A: 48.78 M O Rin = Rg //(Vgs / Igss) Q: The common gate (CG) amplifier differs from both CS and CD configurations in that it has a A: much lower input resistance Q: If you are looking for good voltage gain and high input resistance, you must use a A: CS amplifier Q: For small-signal operation, an n-channel JFET must be biased at A: -Vgs(off) < Vgs < 0 V Q: Two FET amplifiers are cascaded. The first has a voltage gain of 5 and the second has a voltage gain of 7. The overall voltage gain is A: 35 Av(t) = Av1(Av2) = 5 (7) = 35 Q: If there is an internal open between drain and source in a CS amplifier, the drain voltage is equal to A: Vdd Q: The low frequency response of an amplifier is determined in part by A: the coupling capacitors Q: The high frequency response of an amplifier is determined in part by A: the internal transistor capacitances Q: The bandwidth of an amplifier is determined by A: the critical frequencies Q: The gain of an amplifier decreases by 6 dB when the frequency is reduced from 1 kHz to 10 Hz. The roll-off is A: -3 dB / decade 10n = log (1 k /10) n = 2 Roll-off = -6 dB / 2 decade = -3 dB/ decade Q: The gain of a particular amplifier at a given frequency decreases by 6 dB when the frequency is doubled. The roll-off is A: -6 dB / octave Q: The Miller input capacitance of an amplifier is dependent partly on A: the voltage gain Q: An amplifier has the following frequencies: 1.2 kHz, 950 Hz, and 8.5 kHz. The bandwidth is A: 6800 Hz Q: Ideally, the midrange gain of an amplifier A: remains constant with frequency Q: The frequency at which the amplifiers gain is 1 is called A: unity-gain frequency Q: When the voltage gain of an amplifier is increased, the bandwidth A: decreases Q: If the fr of the transistor used in a certain amplifier is 75 MHz and the bandwidth is 10 MHz, the voltage gain must be A: 7.5 fr = Av(mid)BW Q: In the midrange of an amplifiers bandwidth, the peak output voltage is 6 V. At the lower critical frequency, the peak voltage output is A: 4.24 V Vp(lc) = Vp(mid) / \2 Q: At the upper critical frequency, the peak output voltage of a certain amplifier is 10 V. The peak voltage in the midrange of an amplifier is A: 14.14 V Vp(uc) = Vp(mid) / \2 Q: In the step response of a non-inverting amplifier, a longer rise time means A: a narrower bandwidth Q: The lower critical frequency of a direct-coupled amplifier with no bypass capacitor is A: 0 Hz Q: A thyristor has A: 3 pn junctions Q: Common types of thyristor include A: diacs and triacs Q: A Shockley diode turns on when the anode and cathode voltage exceeds A: the forward breakover voltage Q: Once it is conducting, a Shockley diode can be turned off by A: reducing the current below a certain value and disconnecting the anode voltage Q: An SCR differs from the Shockley diode because A: it has a gate terminal Q: An SCR can be turned off by A: forced commutation and anode current interruption but not with a negative pulse on the gate Q: In the forward-blocking region, the SCR is A: in the off state Q: The specified value of holding current for an SCR means that A: the device will turn on when the anode current falls below this value Q: The SCS differs from the SCR because A: it has two gate terminal Q: The SCS can be turned on by A: a positive pulse in the cathode gate or a negative pulse on the anode gate Q: The SCS can be turned off by A: a negative pulse on the cathode gate and the positive pulse on the anode and reducing the anode current to below the holding value Q: The diac is A: a thyristor, a bilateral, two-terminal device and also like two parallel Shockley diodes in reverse directions Q: UJT has the characteristics of A: intrinsic standoff ratio, negative resistance and peak-point voltage but it is not exhibit bilateral conduction Q: In a phototransistor, the base current is A: directly proportional to light Q: The PUT is A: triggered on and off by the gate-to-cathode voltage Q: An integrated circuit (IC) op-amp has A: two inputs and one output Q: Op-amps has A: high gain, high input impedance and low output impedance. It is not necessarily low power. Q: A differential amplifier A: is part of an op-amp and has two outputs Q: When a differential amplifier is operated single-ended, A: one input is grounded and a signal is applied to the other Q: In the differential mode, A: opposite polarity signals are applied to the inputs Q: In the common mode, A: an identical signal appears on both inputs Q: Common mode gain is A: very low Q: Differential gain is A: very high Q: If Av(d) = 3500 and Acm = 0.35, the CMRR is A: 10,000 or 80 dB CMRR = Av(d) / Acm = 3500 / 0.35 = 10,000 Q: The most realistic value for open-loop gain of an op-amp is A: 100,000 Q: A certain op-amp has bias currents of 50 A and 49.3 A. The input offset current is A: 700 nA Ios = |I1 I2| Q: The output of a particular op-amp increases 8 V and 12 s. The slew rate is A: 0.67 V/s Slew rate = AV / At Q: The purpose of offset nulling is A: to zero the output error voltage Q: For an op-amp with negative feedback, the output is A: fed back to the inverting input Q: The use of negative feedback A: reduces the voltage gain of an op-amp and makes linear operation possible Q: Negative feedback __ the input impedance and bandwidth A: increases Q: A certain non-inverting amplifier has an Ri of 1 k O and an Rf of 100 k O. The closed loop gain is A: 101 Av = 1 + Rf / Ri Q: If the feedback resistor of a non-inverting amplifier is open, the voltage gain A: increases Q: A certain inverting amplifier has a closed loop gain of 25. The op-amp has an open-loop gain of 100,000. If another op-amp with an open-loop gain of 200,000 is substituted in the configuration, the closed loop gain A: remains at 25 Q: A voltage follower A: has a gain of 1, is non-inverting and has no feedback resistor Q: The open-loop gain of an op-amp is always A: greater than the closed loop gain Q: The bandwidth of an ac amplifier having a lower critical frequency of 1 kHz and an upper critical frequency of 10 kHz is A: 9 kHz BW = fu - fl Q: The bandwidth of a dc amplifier having an upper critical frequency of 100 kHz is A: 100 khz Q: The frequency at which the open-loop gain is 1 is called A: the unity-gain frequency Q: the mid-range open-loop gain of an op-amp A: extends from 0 Hz to the upper critical frequency Q: Phase shift of an op-amp is caused by A: the internal RC circuits Q: Each RC circuit in an op-amp A: cause the gain to roll off at 6 dB / octave or 20 dB / decade Q: When the negative feedback is used, the gain bandwidth product of an op-amp A: stays the same Q: If the certain op-amp has mid-range open-loop gain of 200,000 and a unity gain frequency of 5 MHz, the gain-bandwidth product is A: 5 MHz Q: If a certain op-amp has a closed-loop gain of 20 and an upper critical frequency of 10 MHz the gain-bandwidth product is A: 200 MHz or 10 MHz if upper critical frequency is the unity-gain frequency Q: Positive feedback occurs when A: the output signal is fed back to the input in-phase with the input signal or when the total phase shift through the op-amp and feedback circuit is 3600 Q: For a closed loop op-amp circuit to be unstable A: there must be positive feedback and the loop gain must be greater than 1 Q: The amount of additional phase shift required to make the total phase shift around a closed loop equal to zero is called A: phase margin Q: For a given value of a closed-loop gain, a positive phase margin indicates A: a stable condition Q: The purpose of a phase-lag compensation is to A: make the op-amp high stable at low values of gain Q: In a zero-level detector, the output changes state when the input A: crosses zero Q: The zero-level detector is one application of a A: comparator Q: Noise on the input of the comparator can cause the output to A: change back and forth erratically between two states Q: The effects of noise can be reduced by A: using positive effects and using hysteresis Q: A comparator with hysteresis A: has two trigger point Q: In a comparator with hysteresis A: a portion of the output is fed back to the non-inverting input Q: Using output bounding in a comparator A: limits the output level Q: A window comparator detects when A: the input is between two specified limits Q: A summing amplifier can have A: any number of inputs Q: If the voltage gain for each input of a summing amplifier with a 4.7 kO feedback resistor is unity, the input resistor must have a value of A: 4.7 k O Q: An averaging amplifier has five inputs. The ratio Rf / Ri must be A: 0.2 Q: In a scaling adder, the input resistors are A: each proportional to the weights of its inputs Q: In an integrator, the feedback element is a A: capacitor Q: For a step input, the output of an integrator is A: a ramp Q: The rate of change of an integrators output voltage in response to a step input is set by A: the RC time constant, the amplitude of the step input and the current through the capacitor Q: In a differentiator, the feedback element is a A: resistor Q: The output of a differentiator is proportional to A: the RC time constant and the rate at which the input is changing Q: When you apply a triangular waveform to the input of a differentiator, the output is A: a square waveform Q: To make a basic instrumentation amplifier, it takes A: three op-amp and seven resistors Q: Typically, an instrumentation amplifier has an external resistor used for A: setting the voltage gain Q: Instrumentation amplifier are used in A: high-noise environments Q: Isolation amplifiers are used primarily in A: applications where there are high voltages and sensitive equipment and applications where human safety is concerned Q: The three sections of a basic amplifier are A: input, output and power Q: The sections of most isolation amplifier are connected by A: transformers Q: The characteristic that allows an isolation amplifier to amplify small signal voltages in the presence of much greater noise voltages is its A: CMRR Q: The term OTA means A: operational transconductance amplifier Q: In an OTA, the transconductance is controlled by A: a bias current Q: The voltage gain of an OTA circuit is set by A: the transconductance and the load resistor Q: An OTA is basically a A: voltage-to-current amplifier Q: The operation of a logarithmic amplifier is based on A: the logarithmic characteristic of a pn junction Q: If the input to a log amplifier is x, the output is proportional to A: nx or 2.3 log10 x Q: If the input to an antilog amplifier is x, the output is proportional to A: e1 Q: The logarithm of the product of two numbers is equal to the A: sum of the logarithms of each of the numbers Q: If you subtract ln y from ln x you get A: ln (x/y) Q: An oscillator differs from an amplifier because A: it requires no input signal Q: All oscillators are based on A: positive feedback Q: One condition for oscillation is A: a phase shift around the feedback loop of 00 Q: A second condition for oscillation is A: a gain of 1 around the feedback loop Q: In a certain oscillator, Av = 50. The attenuation of the feedback circuit must be A: 0.02 Q: For an oscillator to properly start, the gain around the feedback loop must initially be A: greater than 1 Q: In a Wien-bridge oscillator, if the resistances in the positive feedback circuit are decreased, the frequency A: increase Q: The Wien-bridge oscillators positive feedback circuit is A: a lead-lag circuit Q: A phase-shift oscillator has A: three RC circuits Q: Colpitts, Hartley and Clapp are names that refer to A: types of LC oscillator Q: An oscillator whose frequency is changed by a variable dc voltage is known as A: a VCO Q: the main feature of a crystal oscillator is A: stability Q: The operation of a relaxation oscillator is based on A: the charging and discharging of a capacitor Q: Clock is an (input, output, either an input or output, neither an input nor an output) of a 555 timer. A: neither an input nor an output Q: A type of circuit that is capable of locking onto or synchronizing with an incoming signal is called A: a phase-locked loop Q: In the case of a line regulation, when the input voltage changes, the __ stays constant. A: output voltage Q: In the case of a load regulation, when the ___ changes the output voltage stays constant. A: load current Q: What the parts of a voltage regulator? A: control element, sampling circuit, error detector, and reference voltage. Voltage follower is not a part of a voltage regulator. Q: The basic difference between a series regulator and a shunt regulator is A: the position of the control element Q: In a basic series regulator, Vout is determined by A: the sample circuit and the reference voltage Q: The main purpose of a current limiting in a regulator is A: protection of the regulator from excessive current Q: In a linear regulator, the control transistor is conducting A: in a small part of time, half the time, and only when the current is excessive Q: In a switching regulator, the control transistor is conducting A: part of the time Q: The LM 317 is an example of an IC A: three-terminal negative voltage regulator and a switching regulator Q: An external pass transistor is used for A: increasing the current that the regulator can handle Q: The term pole in the filter technology refers to A: one complete active filter Q: An RC circuit can produce a roll-off rate of A: -20 dB / decade or 6 dB / octave Q: A bandpass response has A: two critical frequencies Q: the lowest frequency passed by a low-pass filter is A: 0 Hz Q: the quality factor of a bandpass filter depends on A: the center frequency and the bandwidth Q: The damping factor of an active filter determines A: the response characteristics Q: A maximally flat frequency response is known as A: Butterworth Q: The damping factor of a filter is set by A: the negative feedback circuit Q: The number of poles in a filter affects the A: roll-off rate Q: Sallen-key filters are A: second-order filters Q: When filters are cascaded, the roll-off rate A: increases Q: When a low pass and a high pass filter are cascaded to get a band-pass filter, the critical frequency of the low-pass filter must be A: greater than the frequency of the high-pass filter Q: A state-variable filter consists of A: a summing amplifier and two integrators Q: When the gain of the filter is minimum at its center frequency, it is A: a band-pass filter or a notch filter