ch:7,8

If a counter uses a NAND gate to clear all the flip-flops back to zero immediately after the 1001 count, what is the modulus?

10

A mod-8 counter has how many different output states?

8

What symbol is used inside the flip-flop logic symbol near the clock that says data are transferred to the output on the edge of the pulse?

>

A T flip-flop is any flip-flop with a CLK input.

False

A digital logic pulser is used to measure logic highs and lows.

False

A logic clip cannot be used to simultaneously check the logic level of all pins of a 74HC76 IC.

False

An asynchronous counter is one where all stages of the counter trigger together.

False

Counter clock inputs are always labeled CLK regardless of the manufacturer.

False

Counters are rarely used in almost every digital system.

False

Encoders are sequential logic devices which are widely used temporary memory devices.

False

Encoders sometimes divide frequency and serve as memory units.

False

Latches are available in selected logic families only.

False

The J-K master/slave flip-flop uses just the edge of the pulse to trigger the flip-flop.

False

The basic building block for combinational logic is the flip-flop.

False

The basic building block for sequential logic circuits is the logic gate.

False

The basic building block for sequential logic is the gate.

False

The basic building block for sequential logic is the logic gate.

False

The latch is the least fundamental memory device used in digital electronics.

False

The reflective-type sensor is one of the least common types of optical sensors.

False

A _______________ flip-flop may be formed from a clocked R-S flip-flop by adding an inverter.

Q

_______________ are widely used in signal conditioning.

Schmitt triggers

A bent IC input pin often causes that input to float into the undefined region between a logic low and high.

True

A counter that counts from lower to higher numbers is called an up counter.

True

A device that serves as a temporary buffer memory is called a latch.

True

All IEEE logic symbols are rectangular and include the number of the IC directly above the symbol.

True

Complex digital systems often contain more than one counter.

True

Flip-flops are often wired together to form circuits that count.

True

Flip-flops are wired together to form counters, registers, and memory devices.

True

Hysteresis provides for excellent noise immunity and helps the Schmitt trigger square up waveforms with slow rise and fall times.

True

If a decade counter is connected in series with a mod-6 counter, the result will be a divide-by-60 circuit.

True

One use of a flip-flop is to hold or latch data.

True

Synchronous operation is important in most digital circuits where each step must happen in an exact order.

True

The 74HC85 comparator has three extra inputs used for cascading comparators.

True

The D flip-flop has only one data input and a clock input.

True

The J-K flip-flop has the features of all the other types of flip-flops.

True

The R-S flip-flop is one of several bistable multivibrators.

True

The clocked R-S flip-flop looks almost like an R-S flip-flop except that it has one extra input labeled CLK.

True

The on-off action of a J-K flip-flop is referred to as toggling.

True

The ripple and asynchronous labels mean that all the flip-flops of a counter do not trigger at one time.

True

When the J-K flip-flop is wired for use only in the T mode, it is commonly called a T flip-flop.

True

With a Schmitt trigger, the difference between switching thresholds is called hysteresis.

True

When a flip-flop operates in step with a _______________, it is said to operate synchronously.

clock

A mod-10 counter is often referred to as a(n)

decade counter

Counters are commonly used in digital clocks and frequency counters to

divide frequency

A decade counter connected in series with a _______________ counter will result in a divide-by-80 circuit.

divide-by-80

Which of the following is not an application of a flip-flop?

exclusive or gate

Ripple counters can be constructed from ______________.

flip-flops

How many J-K flip-flops are needed to wire a modulo-16 counter?

four

Schmitt triggers are widely used

in signal conditioning

When the J and K inputs of a J-K flip-flop are both 0, the flip-flop is

in the hold mode

A device that serves as a temporary buffer memory is called a

latch

The most fundamental memory device used in digital electronics is the

latch

The slot-type module and the reflective-type sensor are two common types of

optical sensors

Up or down counters can be stopped after any sequence of counts by using one or more logic _______________.

probes

When the S and R inputs are both 0, both outputs go to a logical 1. This is called a ___________ for the flip-flop.

prohibited state

Digital circuits that contain flip-flops are classified as what type circuits?

sequential

Which of the following is not performed by a counter?

serve as a seven-segment display

The invert bubble at the clock input of a D flip-flop

shows the triggering occurs on the negative-going edge of the clock

Flip-flops that have a clock input are referred to as

synchronous

In a synchronous counter, all stages of the counter trigger _______________.

together

What is the 7475 4-bit latch IC called when the enabled input is high and the normal outputs follow the data at the D inputs?

transparent

Timing diagrams show the _______ and timing between inputs and outputs and are similar to what you would observe on an oscilloscope.

voltage level

_______________ is considered one of the most important troubleshooting tools to have.

your knowledge of the circuit's normal operation

_______________ is the term used when for example, the 10s counter is triggered by the output from the 1s counter while the 100s counter is triggered by the output from the 10s counter

Cascading

When a down counter gets to 000 and recirculates it starts at 001.

False

When both data inputs J and K of a J-K flip-flop are at 1, repeated clock pulses cause the output to remain low.

False

Synchronous counters are most often purchased in _________ form.

IC

The _______________ flip-flop has the features of all the other types of flip-flops.

J-K

Which of the following flip-flops are generally used in counters?

J-K

Digital input devices include clocks, switches, Hall-effect sensors, and pulse-width modulators.

True

In a synchronous counter it is necessary to have all stages of the counter trigger together.

True

In the prohibited state of an R-S flip-flop, the S and the R inputs are both 0 and both outputs go to a logical 1.

True

In the reflective-type optical sensor, one hole is an infrared emitting diode and the other hole is the receiver part of the optical sensor.

True

Latches are commonly organized into groups of 4-bits, 8-bits or more into registers.

True

Sequential logic circuits involve timing and memory.

True

What device can be used to pulse the CLK input of a counter?

a logic pulser

Aside from counting events or periods of time, counters also ________________.

all of these

An instrument used to inject a digital signal into a circuit is called a(n)

digital pulser

What do Schmitt triggers have that cause their switching thresholds to be different for positive-going and negative-going inputs?

hysteresis

What device can check the logic level of all pins simultaneously on a counter IC?

logic clip

Up or down counters can be stopped after any sequence of counts by using a(n) _____.

logic gate

What device can be used to check the logic level on a pin of a counter?

logic probe

The number of different states a counter must go through to complete its counting cycle is called its

modulus