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Home ‣ Digital Electronics ‣ Multivibrators and 555 Timer Comments
- Question
Is the circuit given below an astable multivibrator or a monostable multivibrator?
Options- A. monostable
- B. astable
- Correct Answer
- monostable
- 1. What is the function of the comparators in the 555 timer circuit?
Options- A. to compare the output voltages to the internal voltage divider
- B. to compare the input voltages to the internal voltage divider
- C. to compare the output voltages to the external voltage divider
- D. to compare the input voltages to the external voltage divider Discuss
- 2. The ________ is defined as the time the output is active divided by the total period of the output signal.
Options- A. on time
- B. off time
- C. duty cycle
- D. active ratio Discuss
- 3. If the resistor in the Schmitt trigger astable multivibrator is a variable resistor, what part of the output voltage waveform will change when the resistance is changed?
Options- A. the shape of the waveform
- B. the amplitude of the waveform
- C. the period of the waveform
- D. none of the above Discuss
- 4. Which mode of operation is being used when a 555 timer chip has two external resistors and an external capacitor?
Options- A. monostable
- B. pulse stretching
- C. Schmitt triggering
- D. astable Discuss
- 5. A retriggerable one shot has a pulse of 10 ms. 3 ms after being triggered, another trigger pulse is applied. The resulting output pulse will be ________ ms.
Options- A. 3
- B. 7
- C. 10
- D. 13 Discuss
- 6. 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
- 7. 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
- 8. 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
- 9. Does the 74123 one shot have an internal timing resistor?
Options- A. yes
- B. no Discuss
- 10. 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
Multivibrators and 555 Timer problems
Search Results
Correct Answer: to compare the input voltages to the internal voltage divider
Correct Answer: duty cycle
Correct Answer: the period of the waveform
Correct Answer: astable
Correct Answer: 13
Correct Answer: 0.501 ms
Correct Answer: extend the pulse to this trigger width
Correct Answer: it requires a trigger to obtain an output signal
Correct Answer: no
Correct Answer: discharge the external capacitor to start the timing over again
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