Propagation delay time, tPLH, is measured from the ________. triggering edge of

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Question
Propagation delay time, t_PLH, is measured from the ________.
Options
A. triggering edge of the clock pulse to the LOW-to-HIGH transition of the output
B. triggering edge of the clock pulse to the HIGH-to-LOW transition of the output
C. preset input to the LOW-to-HIGH transition of the output
D. clear input to the HIGH-to-LOW transition of the output

Correct Answer

triggering edge of the clock pulse to the LOW-to-HIGH transition of the output

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1. As a general rule for stable flip-flop triggering, the clock pulse rise and fall times must be:
Options
A. very long.
B. very short.
C. at a maximum value to enable the input control signals to stabilize.
D. of no consequence as long as the levels are within the determinate range of value.

4. The symbols on this flip-flop device indicate ________.
Options
A. triggering takes place on the negative-going edge of the CLK pulse
B. triggering takes place on the positive-going edge of the CLK pulse
C. triggering can take place anytime during the HIGH level of the CLK waveform
D. triggering can take place anytime during the LOW level of the CLK waveform

5. Four positive edge-triggered D flip-flops are used to store a 4-bit binary number as shown below. Determine if the circuit is functioning properly, and if not, what might be wrong.
Options
A. The circuit is functioning properly.
B. Q2 is incorrect; the flip-flop is probably bad.
C. The input to flip-flop 3 (D2) is probably wrong; check the source of D2.
D. A bad connection probably exists between FF-3 and FF-4, causing FF-3 not to reset.

9. An invalid condition in the operation of an active-HIGH input S-R latch occurs when ________.
Options
A. HIGHs are applied simultaneously to both inputs S and R
B. LOWs are applied simultaneously to both inputs S and R
C. a LOW is applied to the S input while a HIGH is applied to the R input
D. a HIGH is applied to the S input while a LOW is applied to the R input

10. The timing network that sets the output frequency of a 555 astable circuit contains ________.
Options
A. three external resistors are used
B. two external resistors and an external capacitor are used
C. an external resistor and two external capacitors are used
D. no external resistor or capacitor is required

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