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Home ‣ Digital Electronics ‣ Multivibrators and 555 Timer Comments
- Question
What controls the output pulse width of a one shot?
Options- A. the clock frequency
- B. the width of the clock pulse
- C. an RL time constant
- D. an RC time constant
- Correct Answer
- an RC time constant
- 1. What does the discharge transistor do in the 555 timer circuit?
Options- A. charge the external capacitor to stop the timing
- B. charge the external capacitor to start the timing over again
- C. discharge the external capacitor to stop the timing
- D. discharge the external capacitor to start the timing over again Discuss
- 2. Does the 74123 one shot have an internal timing resistor?
Options- A. yes
- B. no Discuss
- 3. The monostable multivibrator circuit is not an oscillator because ________.
Options- A. its output switches between two states
- B. it requires a trigger to obtain an output signal
- C. it requires a sine wave input signal
- D. the circuit does not require a dc power supply Discuss
- 4. Triggering a retriggerable one shot during pulse generation will:
Options- A. time out the original pulse
- B. extend the pulse to this trigger width
- C. have no effect
- D. double the original pulse width Discuss
- 5. A 22-kΩ resistor and a 0.02-µF capacitor are connected in series to a 5-V source. How long will it take the capacitor to charge to 3.4 V?
Options- A. 0.44 ms
- B. 0.501 ms
- C. 0.66 ms
- D. 0.70 ms Discuss
- 6. The internal circuitry of the 555 timer consists of ________, an R-S flip-flop, a transistor switch, an output buffer amplifier, and a voltage divider.
Options- A. a comparator
- B. a voltage amplifier
- C. two comparators
- D. a peak detector Discuss
- 7. What is the duty cycle of the waveform at the output of the circuit given below?
Options- A. 78%
- B. 56%
- C. 50%
- D. 44% Discuss
- 8. Design a circuit using a 74121 to convert a 33-kHz, 30% duty cycle waveform to a 33-kHz, 60% duty cycle waveform.
Options- A. Rint = 2 kΩ, Cext = 0.012 nF
- B. Rint = 2 kΩ, Cext = 0.012 µF
- C. Rint = 4 kΩ, Cext = 0.012 nF
- D. Rint = 4 kΩ, Cext = 0.012 µF Discuss
- 9. What is the pulse width of the output of a 74123 if an external 4.7-kΩ resistor and a 0.022-µF capacitor are used?
Options- A. 290 ms
- B. 29 ms
- C. 33.3 µs
- D. 290 µs Discuss
- 10. A monostable 555 timer has the following number of stable states:
Options- A. 0
- B. 1
- C. 2
- D. 3 Discuss
Multivibrators and 555 Timer problems
Search Results
Correct Answer: discharge the external capacitor to start the timing over again
Correct Answer: no
Correct Answer: it requires a trigger to obtain an output signal
Correct Answer: extend the pulse to this trigger width
Correct Answer: 0.501 ms
Correct Answer: two comparators
Correct Answer: 56%
Correct Answer: Rint = 2 kΩ, Cext = 0.012 µF
Correct Answer: 33.3 µs
Correct Answer: 1
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