Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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A ________ occurs when the
inputs to a J-K flip-flop change at the same time that the active trigger edge makes its
transition.
a. | race
condition | c. | RESET
condition | b. | TOGGLE state | d. | propagation delay |
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2.
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The J and K inputs must be
active for a minimum length of time prior to the active clock edge. This time parameter is
called
a. | propagation
delay. | c. | race
time. | b. | setup time. | d. | trigger time. |
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3.
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The setup time for a typical
TTL J-K flip-flop (such as the 74LS76) is
a. | 25 ìsec. | c. | 20
nsec. | b. | 4 nsec. | d. | 100 ìsec. |
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4.
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Typical propagation delay for a
TTL J-K flip-flop (such as the 74LS76) is
a. | 85
nsec. | c. | 5
nsec. | b. | 30 nsec. | d. | 500 nsec. |
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5.
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The amount of time the inputs
must be held steady after a trigger pulse occurs is known as
a. | race
time. | c. | setup
time. | b. | propagation delay. | d. | hold time. |
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6.
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The nominal Vcc supply voltage
required by a TTL flip-flop such as the 74LS76 is
a. | 4.5 V. | c. | 7.0 V. | b. | 4.0 V. | d. | 5.0 V. |
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7.
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The temperature range for
commercial TTL flip-flops (such as the 74LS76) is
a. | 0 to 70 degrees
C. | c. | 0 to 125 degrees
C. | b. | 0 to 100 degrees
C. | d. | -50 to +50 degrees
C. |
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8.
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To which pin is Vcc connected
on a 7476 flip-flop? (Refer to Figure 11-11 in your textbook.)
a. | pin 7 | c. | pin 13 | b. | pin 16 | d. | pin 5 |
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9.
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What is the maximum LOW-level
output current of a 7476 flip-flop? (Refer to Figure 11-11 in your textbook.)
a. | 6 mA | c. | -400 ìA | b. | 4 mA | d. | 16
mA |
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10.
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When using the SET and RESET
inputs on a 7476 flip-flop, what is the propagation delay for a HIGH to LOW output change? (Refer to
Figure 11-11 in your textbook.)
a. | 15 ns | c. | 60 ns | b. | 25 ns | d. | 40 ns |
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11.
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Automatic reset circuitry for
digital devices usually use
a. | setup
time. | c. | toggle
states. | b. | RC circuits. | d. | complex ICs. |
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12.
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A transformer and bridge power
supply circuit is a good source of which of the following?
a. | 5 V supply
voltage | c. | hysteresis | b. | clock signal | d. | A and B only |
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13.
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LEDs can be energized by
connecting
a. | cathodes to digital outputs through
a resistance. | b. | anodes to digital outputs through a
resistance. | c. | anodes directly to digital outputs. | d. | cathodes directly to digital
outputs. |
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14.
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An integrated circuit with an
LED and photo transistor encased in the same package is called a(n)
a. | optocoupler. | c. | amplifier. | b. | J-K flip-flop. | d. | photo resistor. |
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15.
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An optical interrupter switch
is a special form of the
a. | J-K
flip-flop. | c. | optocoupler. | b. | photo cell. | d. | laser. |
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16.
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The Hall-effect switch is
usually packaged as a ________-terminal device.
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17.
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________ is a term used in
digital electronics to describe a waveform that has some degree of electrical noise on
it.
a. | Ripple | c. | Hysteresis | b. | Duty cycle | d. | Jitter |
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18.
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A ________ is an electronic
device used to convert an ac voltage into a dc voltage.
a. | pull-up
resistor | c. | rectifier | b. | Schmitt trigger | d. | photo transistor |
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