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Home ‣ Digital Electronics ‣ Multivibrators and 555 Timer Comments
- Question
With most monostable multivibrators, what is the Q output when no input trigger has occurred?
Options- A. LOW
- B. +5 V
- C. SET
- D. HIGH
- Correct Answer
- LOW
- 1. Which of the following is NOT a characteristic of a retriggerable monostable multivibrator?
Options- A. It is a dual multivibrator.
- B. It has an active-HIGH reset, which terminates all timing functions.
- C. It has no internal timing resistor.
- D. none of the above Discuss
- 2. What is the difference between a retriggerable one shot and a nonretriggerable one shot?
Options- A. The nonretriggerable can only be triggered once.
- B. The retriggerable can be triggered many times.
- C. The output pulse can be stretched with a nonretriggerable.
- D. The output pulse can be stretched with a retriggerable. Discuss
- 3. Pulse stretching, time-delay, and pulse generation are all easily accomplished with which type of multivibrator circuit?
Options- A. astable
- B. monostable
- C. multistable
- D. bistable Discuss
- 4. A monostable 555 timer has the following number of stable states:
Options- A. 0
- B. 1
- C. 2
- D. 3 Discuss
- 5. 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
- 6. The output of the astable circuit ________.
Options- A. constantly switches between two states
- B. is LOW until a trigger is received
- C. is HIGH until a trigger is received
- D. floats until triggered Discuss
- 7. When a capacitor charges:
Options- A. the voltage across the plates rises exponentially
- B. the circuit current falls exponentially
- C. the capacitor charges to the source voltage in 5×RC seconds
- D. all of the above Discuss
- 8. The pulse width out of a one-shot multivibrator increases when the:
Options- A. supply voltage increases
- B. timing resistor decreases
- C. UTP decreases
- D. timing capacitance increases Discuss
- 9. What is another name for a bistable multivibrator?
Options- A. an on-off switch
- B. an oscillator
- C. a flip-flop Discuss
- 10. A 0.3-µF capacitor has an initial charge of 2.7 V. If it is discharged through a 10-kΩ resistor for 6.5 ms, how much voltage will be left across the capacitor?
Options- A. 0.0 V
- B. 0.309 V
- C. 2.7 V
- D. 2.295 V Discuss
Multivibrators and 555 Timer problems
Search Results
Correct Answer: It has an active-HIGH reset, which terminates all timing functions.
Correct Answer: The output pulse can be stretched with a retriggerable.
Correct Answer: monostable
Correct Answer: 1
Correct Answer: 33.3 µs
Correct Answer: constantly switches between two states
Correct Answer: all of the above
Correct Answer: supply voltage increases
Correct Answer: a flip-flop
Correct Answer: 0.309 V
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