Digital Electronics - Multivibrators and 555 Timer

Exercise :: Multivibrators and 555 Timer - General Questions

16. 

Design a circuit using a 74121 to convert a 33-kHz, 30% duty cycle waveform to a 33-kHz, 60% duty cycle waveform.

A. Rint = 2 k, Cext = 0.012 nF
B. Rint = 2 k, Cext = 0.012 F
C. Rint = 4 k, Cext = 0.012 nF
D. Rint = 4 k, Cext = 0.012 F

Answer: Option B

Explanation:

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17. 

What controls the output pulse width of a one shot?

A. the clock frequency
B. the width of the clock pulse
C. an RL time constant
D. an RC time constant

Answer: Option D

Explanation:

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18. 

Does the 74123 one shot have an internal timing resistor?

A. yes
B. no

Answer: Option B

Explanation:

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19. 

In a typical IC monostable multivibrator circuit, at the falling edge of the trigger input, the output switches HIGH for a period of time determined by the ________.

A. value of the RC timing components
B. amplitude of the input trigger
C. frequency of the input trigger
D. magnitude of the dc supply voltage

Answer: Option A

Explanation:

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20. 

A monostable 555 timer has the following number of stable states:

A. 0
B. 1
C. 2
D. 3

Answer: Option B

Explanation:

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