ch,6,7

What is the 8421 BCD code equivalent for the decimal number 36?

0011 0110

What is the decimal number for the BCD number 0010 1001 0111?

297

How many leads exit the unipolar motor?

5 or more

The most popular 7-bit alphanumeric code is

ASCII

Excellent noise immunity is a characteristic of which logic family?

CMOS

A Schmitt trigger can change a square wave into a sine wave.

False

A decoder is an electronic device that translates from decimal to an encrypted code such as binary.

False

A relay cannot isolate a logic device from a high-voltage circuit.

False

A simple permanent magnet dc motor is typically used for angular positioning of a shaft.

False

Advantages of BJTs are their low power requirements and good noise immunity.

False

If seven-segment displays need to show decimal digits 0 through 9, the hexadecimal code should be used.

False

In a BCD-to-seven-segment decoder/driver, blanking causes all LEDs on the display to light.

False

Inverters are combinational logic circuits with several inputs and outputs.

False

Newer color LCDs are generally classified as active-matrix LCDs.

False

The LED is nothing like a PN-junction diode.

False

The cathodes of the vacuum fluorescent display tube are shaped like segments of a number or other shapes.

False

The gray code can be used in arithmetic circuits.

False

The load represented by a single gate is called the fan-out of that family of ICs.

False

The slight delay between the time the input changes and the time the output changes is called the time constant of a TTL inverter.

False

This code is not classified as a BCD type code.

Gray code

_______________ sensors are magnetically-activated sensors or switches.

Hall-effect

_______________ in a digital system is unwanted voltages induced in the connecting wires and printed circuit board traces that might affect the input logic levels.

Noise

Which of the following is not true of an electromechanical relay?

They are also called optoisolators.

A device known as a clamp diode is placed across a relay coil to prevent voltage spikes from being induced into a system.

True

A practical alternative to an electromagnetic relay when interfacing with digital circuits is the optocoupler.

True

A very common output device used to display decimal numbers is the seven-segment display.

True

Because the 74147 encoder has a priority feature, when two inputs are activated at the same time only the larger number will be encoded.

True

Inexpensive monochrome LCDs use the twisted-nematic field-effect technology.

True

Integrated circuits within a logic family are designed to interface easily with one another.

True

Interfacing is the design of the interconnections between circuits that shift the levels of voltage and current to make them compatible.

True

MOS devices use less space on a silicon chip than do other devices.

True

Manufacturers specify that for correct operation, a high input must range from 2.0 to 5.5 volts.

True

Pull-up resistors and special interface ICs are typically used as an interface between different logic families.

True

Since the display driver is generally packaged in the same IC as a decoder, it often referred to as a seven-segment decoder/driver.

True

The 8421 binary-coded decimal code is frequently referred to as the BCD code.

True

The LCD has the advantage of very low power consumption and is well suited for use in brightly lit areas.

True

The binary code is used to represent various forms of binary.

True

The light-emitting diode generally operates at low currents and voltages.

True

The standard ASCII code is a 7-bit code used in transferring coded information from keyboards and to computer displays and printers.

True

The standard TTL output can sink up to 16 mA.

True

To convert a decimal number to the excess-3 form, add 3 to each digit of the decimal number and convert to binary form.

True

An excellent method of isolating a logic device from a high-voltage circuit is

a relay

A motor in which either the angular position or speed can be controlled precisely by a servo loop which uses feedback from output to input for control is called

a servo motor

A typical optoisolator contains

an infrared-emitting diode

What is the switching threshold for standard TTL logic gate inputs?

between 0.8 and 2.0 V

The process of causing all LEDs on the display to remain unlit is called

blanking

Decoders are _______________ logic circuits with several inputs and outputs.

combinational

It is recommended that pins of CMOS ICs be stored in

conductive foam

The objective of many electromechanical systems is to

control a simple output device

An LED generates light and the LCD

controls light

A logic device that translates from an encrypted code into a code that is more understandable is the

decoder

The ¬fan-out of a digital IC is the number of ____________ that can be driven by the gate's output.

drive capabilities

The ________________ of CMOS ICs make them ideal for battery-operated portable devices.

extremely high power consumption

What type of seven-segment display emits a reddish glow?

light-emitting diode

Usually power for the _______________ is provided by a display driver IC.

logic probe

The liquid-crystal display creates _______________ in a black or silvery color.

numbers

About three-quarters of all faults in digital circuits occur because of _________________________.

open input or output circuits

A modern signaling device drawing much less current than older buzzers and bells is the

piezo buzzer

The smallest element that can light or not light on a CRT or LCD monitor is the

pixel

The three parts of the triode tube are the

plate, cathode, and grid

The pulse width used with a servo motor can be changed by the operator by using a

potentiometer

An incandescent display is similar to a _______________.

regular lamp

The output voltage of the Hall-effect sensor is

small and is commonly amplified

What type motor can rotate a fixed angle with each input pulse?

stepper

Applying 1.6 V to a TTL input is interpreted by the IC as what logic level?

undefined

When troubleshooting a decoder circuit

use senses first

The seven-segment display that emits a blue-green glow when lit and is very compatible with low voltages is the

vacuum fluorescent type

Which of the following is used in most color TVs and computer monitors?

vacuum tube technology