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- Question
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
- Correct Answer
- Rint = 2 kΩ, Cext = 0.012 µF
- 1. The PAL has an AND and OR structure similar to a PROM, but in the PAL the inputs to the AND gates are programmable, whereas the inputs to the OR gate are hard-wired.
Options- A. True
- B. False Discuss
- 2. One of the first steps in any HDL project is to define its scope by naming each input and output.
Options- A. True
- B. False Discuss
- 3. The basic part numbers of ICs are the same regardless of the manufacturer because digital logic ICs have been standardized.
Options- A. True
- B. False Discuss
- 4. The duty cycle of a 555 timer configured as a basic astable multivibrator is controlled by ________.
Options- A. one resistor
- B. two resistors
- C. one capacitor
- D. a resistor and a capacitor Discuss
- 5. The major advantage of TTL logic circuits over CMOS is lower propagation delay.
Options- A. True
- B. False Discuss
- 6. The commutative law of addition and multiplication indicates that:
Options- A. we can group variables in an AND or in an OR any way we want
- B. an expression can be expanded by multiplying term by term just the same as in ordinary algebra
- C. the way we OR or AND two variables is unimportant because the result is the same
- D. the factoring of Boolean expressions requires the multiplication of product terms that contain like variables Discuss
- 7. What is the name of a digital circuit that produces several repetitive digital waveforms?
Options- A. an inverter
- B. an OR gate
- C. a Johnson shift counter
- D. an AND gate Discuss
- 8. The stability of the ADC process can be improved by using a(n) ________ to hold the analog voltage constant while the A/D conversion is taking place.
Options- A. sample-and-hold circuit
- B. op-amp comparator
- C. NPN amp
- D. current loop Discuss
- 9. There are many applications in which analog data must be digitized and transferred into a computer's memory. The process by which the computer acquires these digitized analog data is referred to as ________.
Options- A. sampling
- B. multiplexing
- C. data acquisition
- D. prescaling Discuss
- 10. An alternate function of port pin P3.4 in the 8051 is:
Options- A. Timer 0
- B. Timer 1
- C. interrupt 0
- D. interrupt 1 Discuss
More questions
Correct Answer: True
Correct Answer: True
Correct Answer: True
Correct Answer: a resistor and a capacitor
Correct Answer: True
Correct Answer: the way we OR or AND two variables is unimportant because the result is the same
Correct Answer: a Johnson shift counter
Correct Answer: sample-and-hold circuit
Correct Answer: data acquisition
Correct Answer: Timer 0
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