Digital Electronics - Multivibrators and 555 Timer

Exercise :: Multivibrators and 555 Timer - General Questions

11. 

What is the difference between an astable multivibrator and a monostable multivibrator?

A. The astable is free running.
B. The astable needs to be clocked.
C. The monostable is free running.
D. none of the above

Answer: Option A

Explanation:

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12. 

Is there any limit to the number of times that a 74123 can be retriggered?

A. yes
B. no

Answer: Option B

Explanation:

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13. 

Determine tHI and tLO for the circuit given below.

A. tHI = 7.95 s, tLO = 6.24 s
B. tHI = 6.24 s, tLO = 7.95 s
C. tHI = 3.97 s, tLO = 3.21 s
D. tHI = 3.21 s, tLO = 3.97 s

Answer: Option A

Explanation:

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14. 

The output of the astable circuit ________.

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

Answer: Option A

Explanation:

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15. 

If a diode is connected across resistor RB (positive end up) in the given figure, what is the new duty cycle of the output waveform?

A. 56%
B. 44%
C. 21.6%
D. 17.4%

Answer: Option C

Explanation:

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