A 555 operating as a monostable multivibrator has a C1 = 100 �F. Determine R1 fo

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Question
A 555 operating as a monostable multivibrator has a C₁ = 100 µF. Determine R₁ for a pulse width of 500 ms.
Options
A. 45 Ω
B. 455Ω
C. 4.5 kΩ
D. 455 kΩ

Correct Answer

4.5 kΩ

Flip-Flops problems

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2. 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

3. 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.

5. Which of the following describes the operation of a positive edge-triggered D flip-flop?
Options
A. If both inputs are HIGH, the output will toggle.
B. The output will follow the input on the leading edge of the clock.
C. When both inputs are LOW, an invalid state exists.
D. The input is toggled into the flip-flop on the leading edge of the clock and is passed to the output on the trailing edge of the clock.

6. 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.

7. 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

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