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Home ‣ Digital Electronics ‣ Logic Families and Their Characteristics Comments
- Question
The time needed for an output to change from the result of an input change is known as:
Options- A. noise immunity
- B. fan-out
- C. propagation delay
- D. rise time
- Correct Answer
- propagation delay
- 1. What should be done to unused inputs on TTL gates?
Options- A. They should be left disconnected so as not to produce a load on any of the other circuits and to minimize power loading on the voltage source.
- B. All unused gates should be connected together and tied to V
- C. All unused inputs should be connected to an unused output; this will ensure compatible loading on both the unused inputs and unused outputs.
- D. Unused AND and NAND inputs should be tied to VCC through a 1 kΩ resistor; unused OR and NOR inputs should be grounded. Discuss
- 2. The output current capability of a single 7400 NAND gate when HIGH is called ________.
Options- A. source current
- B. sink current
- C. IOH
- D. source current of IOH Discuss
- 3. Why is a pull-up resistor needed when connecting TTL logic to CMOS logic?
Options- A. to increase the output LOW voltage
- B. to decrease the output LOW voltage
- C. to increase the output HIGH voltage
- D. to decrease the output HIGH voltage Discuss
- 4. Fan-out is determined by taking the ________ result(s) of ________.
Options- A. smaller,
- B. larger,
- C. smaller,
- D. average,
Discuss
- 5. Assume that a particular IC has a supply voltage (Vcc) equal to +5 V and ICCH = 10 mA and ICCL = 23 mA. What is the power dissipation for the chip?
Options- A. 50 mW
- B. 82.5 mW
- C. 115 mW
- D. 165 mW Discuss
- 6. Why are the maximum value of VOL and the minimum value of VOH used to determine the noise margin rather than the typical values for these parameters?
Options- A. These are worst-case conditions.
- B. These are normal conditions.
- C. These are best-case conditions.
- D. It doesn't matter what values are used. Discuss
- 7. The term buffer/driver signifies the ability to provide low output currents to drive light loads.
Options- A. True
- B. False Discuss
- 8. Using the schematic diagram of a TTL NAND gate, determine the state of each transistor (ON or OFF) when all inputs are high.
Options- A. Q1-ON, Q2-OFF, Q3-ON, Q4-OFF
- B. Q1-ON, Q2-ON, Q3-OFF, Q4-OFF
- C. Q1-OFF, Q2-OFF, Q3-ON, Q4-ON
- D. Q1-OFF, Q2-ON, Q3-OFF, Q4-ON Discuss
- 9. When is a level-shifter circuit needed in interfacing logic?
Options- A. A level shifter is always needed.
- B. A level shifter is never needed.
- C. when the supply voltages are the same
- D. when the supply voltages are different Discuss
- 10. What is the advantage of using low-power Schottky (LS) over standard TTL logic?
Options- A. more power dissipation
- B. less power dissipation
- C. cost is less
- D. cost is more Discuss
Logic Families and Their Characteristics problems
Search Results
Correct Answer: Unused AND and NAND inputs should be tied to VCC through a 1 kΩ resistor; unused OR and NOR inputs should be grounded.
Correct Answer: source current
Correct Answer: to increase the output HIGH voltage
Correct Answer: smaller,
Correct Answer: 82.5 mW
Correct Answer: These are worst-case conditions.
Correct Answer: False
Correct Answer: Q1-OFF, Q2-ON, Q3-OFF, Q4-ON
Correct Answer: when the supply voltages are different
Correct Answer: less power dissipation
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