ELEX (FLOYD 5)

a. Two critical frequencies

A band-pass response has a. Two critical frequencies b. Critical frequency c. A flat curve in the passband d. A wide bandwidth

b. Reduces output error voltage

Bias current compensation a. Reduces gain b. Reduces output error voltage c. Increases bandwidth d. Has no effect

a. Above the critical frequency

In a high-pass filter, the roll-off occurs a. Above the critical frequency b. Below the critical frequency c. During the mid-range d. At the center frequency

c. each proportional to the weight of its input

In a scaling adder, the input resistors are a. all the same value b. all of different values c. each proportional to the weight of its input d. related by a factor of two

c. crosses zero

In a zero-level detector, the output changes state when the input a. Is positive b. Is negative c. crosses zero d. has a zero rate of change

b. capacitor

In an ideal integrator, the feedback element is a a. resistor b. capacitor c. zener diode d. voltage divider

a. high noise environments

Instrumentation amplifiers are used primarily in a. high noise environments b. medical equipment c. test instruments d. filter circuits

c. The center frequency and the bandwidth

The quality factor (Q) of a band-pass filter depends on a. The critical frequencies b. Only the bandwidth c. The center frequency and the bandwidth d. Only the center frequency

d. RC time constant, amplitude of the step input, current through the capacitor

The rate of change of an integrator's output voltage in response to step input is set by a. the RC time constant b. the amplitude of the step input c. the current through the capacitor d. RC time constant, amplitude of the step input, current through the capacitor

b. a capacitor

The stages of many isolation amplifiers are connected by a. copper strips b. a capacitor c. microwave links d. current loops

c. operational transconductance amplifier

The term OTA means a. operational transistor amplifier b. operational transformer amplifier c. operational transconductance amplifier d. output transducer amplifier

c. a single RC circuit

The term pole in filter terminology refers to a. a high-gain op-amp b. one complete active filter c. a single RC circuit d. the feedback circuit

c. input stage and output stage

The two parts of basic isolation amplifier are a. amplifier and filter b. input stage and coupling stage c. input stage and output stage d. gain stage and offset stage

c. the transconductance and the load resistance

The voltage of an OTA circuit is set by a. a feedback resistor b. the transconductance only c. the transconductance and the load resistance d. the bias current and supply voltage

a. comparator

The zero-level detector is one application of a a. comparator b. differentiator c. summing amplifier d. diode

d. three op-amps and seven resistors

To make a basic instrumentation amplifier, it takes a. one op-amp with a certain feedback arrangement b. two op-amps and seven resistors c. three op-amps and seven capacitors d. three op-amps and seven resistors

b. setting the voltage gain

Typically, an instrumentation amplifier has an external resistor used for a. establishing the input impedance b. setting the voltage gain c. setting the current gain d. interacing with an instrument

c. limits the output levels

Using output bounding in a comparator a. makes it faster b. keeps the output positive c. limits the output levels d. stabilizes the output

c. Greater than the critical frequency og the high-pass filter

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. Equal to the critical frequency of the high-pass filter b. Less than the critical frequency of the high-pass filter c. Greater than the critical frequency og the high-pass filter

a. Increases

When low-pass filters are cascaded, the roll- off rate a. Increases b. Decreases c. Does not change

c. Stays the same

When negative feedback is used, the gain- bandwidth product of an op-amp a. Increases b. Decreases c. Stays the same d. Fluctuates

c. a square waveform

When you apply a triangular waveform to the input of a differentiator, the output is a. a dc level b. an inverted triangular waveform c. a square waveform d. the first harmonic of the triangular waveform

d. a bias current

in an OTA, the transconductance is controlled by a. the DC supply voltage b. the input signal voltage c. the manufacturing process d. a bias current

c. Remains at 25

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 200000 is substituted in the configuration, the closed-loop gain a. Doubles b. Drops to 12.5 c. Remains at 25

a. Increases

A certain noninverting amplifier has an Ri of 1 kΩ and an Rf of 100 kΩ. If the feedback resistor in Question 16 is open, the voltage gain a. Increases b. Decreases c. In not affected d. Depends on Ri

c. 101

A certain noninverting amplifier has an Ri of 1 kΩ and an Rf of 100 kΩ. The closed-loop gain is a. 100000 b. 1000 c. 101 d. 100

b. has two trigger points

A comparator with hysteresis a. has one trigger point b. has two trigger points c. has a variable trigger point d. is like a magnetic circuit

c. for all values of load resistance within defined limits

A constant-current source provides a non- changing current to the load a. for all values of current b. for all values of load resistance c. for all values of load resistance within defined limits

b. Butterworth

A maximally flat frequency response is known as a. Chebyshev b. Butterworth c. Bessel d. Colpitts

b. a comparator, a diode and a capacitor

A peak detector consists of a. a comparator, a transistor and a capacitor b. a comparator, a diode and a capacitor c. a comparator, a diode and an inductor d. an integrator, a diode and a capacitor

d. -20dB/decade and -6 dB/octave

A single resistor and a single capacitor can be connected to form a filter with a roll-off rate of a. -20dB/decade b. -40 dB/decade c. -6 dB/octave d. -20dB/decade and -6 dB/octave

b. A summing amplifier and two integrators

A state-variable filter consist of a. One op-amp with multiple-feedback paths b. A summing amplifier and two integrators c. A summing amplifier and two differentiators d. Three Butterworth stages

c. any number of inputs

A summing amplifier can have a. only one input b. only two inputs c. any number of inputs

d. Two capacitors and two resistors and A feedback circuit

A two-pole Sallen-Key high-pass filter contains a. one capacitor and two resistors b. Two capacitors and two resistors c. A feedback circuit d. Two capacitors and two resistors and A feedback circuit

d. Has all of these

A voltage-follower a. Has a gain of 1 b. Is noninverting c. Has no feedback resistor d. Has all of these

a. voltage-to-current amplifier

An OTA is basically a a. voltage-to-current amplifier b. current-to-voltage amplifier c. current-to-current amplifier d. voltage-to-voltage amplifier

b. 0.2

An averaging amplifier has five inputs. The ratio Rf/Ri must be a. 5 b. 0.2 c. 1

a. resistor

In a differentiator, the feedback element is a a. resistor b. capacitor c. zener diode d. voltagedivider

d. Causes the gain to roll off at -6 dB/octave and Causes the gain to foll off at -20 dB/decade

Each RC circuit in an op-amp a. Causes the gain to roll off at -6 dB/octave b. Causes the gain to foll off at -20 dB/decade c. Reduces the midrange gain by 3 dB d. Causes the gain to roll off at -6 dB/octave and Causes the gain to foll off at -20 dB/decade

d. a ramp

For a step input, the output of an integrator is a. a pulse b. a triangular waveform c. a spike d. a ramp

c. Fed back to the inverting input

For an op-amp with negative feedback, the output is a. Equal to the input b. Increased c. Fed back to the inverting input d. Fed back to the noninverting input

d. 200 Mhz and unity-gain frequency

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 b. 10 Mhz c. The unity-gain frequency d. 200 Mhz and unity-gain frequency

b. 5,000,000Hz

If a certain op-amp has a midrange open- loop gain of 200,000 and a unity-gain frequency of 5 MHz, the gain-bandwidth product is a. 200000Hz b. 5,000,000Hz c. 1x1012 Hz d. Not determinable from the information

e.lnx and 2.3 log10 x

If the input to a log amplifier is x, the output is proportional to a. ex b. lnx c. log10 x d. 2.3 log10 x e.lnx and 2.3 log10 x

b. e^x

If the input to an antilog amplifier is x, the output is proportional to a. elnx b. e^x c. lnx d. e^-x

a. 4.7 kΩ

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

d. a portion of the output is fed back to the non-inverting input

In a comparator with hysteresis a. a bias voltage is applied between the two inputs b. only one supply voltage is used c. a portion of the output is fed back to the inverting input d. a portion of the output is fed back to the non-inverting input

e. applications where there are high voltages and sensitive equipment and applications where human safety is concern

Isolation amplifiers are used primarily in a. remote, isolated locations b. systems that isolate a single signal from many different signals c. applications where there are high voltages and sensitive equipment d. applications where human safety is concern e. applications where there are high voltages and sensitive equipment and applications where human safety is concern

b. Increases the input impedance and the bandwidth

Negative feedback a. Increases the input and output impedances b. Increases the input impedance and the bandwidth c. Decreases the output impedance and the bandwidth d. Does not affect impedances or bandwidth

c. change back and forth erratically between two states

Noise on the input of a comparator can cause the output to a. hang up in one state b. go to zero c. change back and forth erratically between two states d. produce the amplified noise signal

a. The internal RC circuits

Phase shift through an op-amp is caused by a. The internal RC circuits b. The external RC circuits c. The gain roll-off d. Negativefeedback

b. Second-order filters

Sallen-key low pass filter are a. Single-pole filters b. Second-order filters c. Butterworth filters d. Bandpass filters

a. 100 kHz

The bandwidth of a dc amplifier having an upper critical frequency of 100 kHz is a. 100 kHz b. Unknown c. Infinity d. 0Khz

b. 9kHz

The bandwidth of an ac amplifier having a lower critical frequency of 1 khz and an upper critical frequency of 10 kHz is a. 1kHz b. 9kHz c. 10 kHz d. 11 kHz

a. CMRR

The characteristic that allows an isolation amplifier to amplify small signal voltages in the presence of much greater noise voltages is its a. CMRR b. high gain c. high input impedance d. magnetic coupling between input and output

a. The negative feedback circuit

The damping factor of a filter is set by a. The negative feedback circuit b. The positive feedback circuit c. The frequency-selective circuit d. The gain of the op-amp

c. The response characteristic

The damping factor of an active filter determines a. The voltage gain b. The critical frequency c. The response characteristic d. The roll-off rate

e. using positive feedback and hysteresis

The effects of noise can be reduced by a. lowering the supply voltage b. using positive feedback c. using negative feedback d. using hysteresis e. using positive feedback and hysteresis

d. The unity-gain frequency

The frequency at which the open-loop gain is equal to 1 is called a. The upper critical frequency b. The cutoff frequency c. The notch frequency d. The unity-gain frequency

b. 0Hz

The lowest frequency passed by a low-pass filter is a. 1Hz b. 0Hz c. 10 Hz d. Dependent on the critical frequency

b. Extends from 0 Hz to the upper critical frequency

The midrange open-loop gain of an op-amp a. Extends from the lower critical frequency to the upper critical frequency b. Extends from 0 Hz to the upper critical frequency c. Rolls off at 20 dB/decade beginning at 0Hz

d. Roll-off rate

The number of poles in a filter affect the a. Voltage gain b. Bandwidth c. Center frequency d. Roll-off rate

b. the logarithmic characteristic of a pn junction

The operations of a logarithmic amplifier is based on a. the nonlinear operation of an op-amp b. the logarithmic characteristic of a pn junction c. the reverse breakdown characteristic of a pn junction d. the logarithmic charge and discharge of an RC circuit

d. RC time constant and rate at which the input is changing

The output of a differentiator is proportional to a. the RC time constant b. the rate at which the input is changing c. the amplitude of the input d. RC time constant and rate at which the input is changing