# Logic Families Questions and Answers

1. Which of the following is the most widely employed logic family?

a) Emitter-coupled logic
b) Transistor-transistor logic
c) CMOS logic family
d) NMOS logic

Explanation: Transistor-transistor logic is the most widely employed logic family. It is the most popular logic family.

2. The basic function of TTL gate is which of the following functions?

a) AND
b) OR
c) NOR
d) NAND

Explanation: The basic function of TTL gate is NAND function. It is the most popular logic family.

3. In TTL logic, the input transistor has a number of ________ equal to the desired fan-in of the circuit.

a) Base
b) Collect
c) Emitter
d) Gate

Explanation: In TTL logic, the input transistor has a number of emitter equal to the desired fan-in of the circuit. This is a major advantage.

4. Which of the following is the propagation delay of TTL circuits?

a) 1 s
b) 1 ms
c) 1 ns
d) 1 ps

Explanation: The propagation delay of TTL circuit is 1 ns. It is a main characteristic of TTL circuit.

5. The standard TTL gates are marketed as _______ series.

a) 80
b) 82
c) 74
d) 08

Explanation: The standard TTL gates are marketed as 74 series. They can operate up to 700C.

6. Schottky TTL logic family does not have which of the following features?

a) Good fan-in
b) Good fan-out
c) High speed capability
d) High propagation delay

Explanation: Schottky TTL circuits have reduced propagation delay than normal TTL circuits. The propagation delay of 10ns is very high for some applications.

7. The logic ‘0’ of ECL is represented as ______V and logic ‘1’ is represented as ______V.

a) 1, 1.65
b) 0.9, 1.75
c) 1.2, 2.35
d) 1.9, 4.3

Explanation: The logic ‘0’ of ECL is represented as 0.9 V and logic ‘1’ is represented as 1.75 V. ECL stands for emitter-coupled logic.

8. ECL is a way of achieving higher speed of gate.

a) True
b) False

Explanation: We can achieve high speed of gate by sing ECL. ECL stands for emitter-coupled logic.

9. Which of the following is not the advantage of MOS gates?

a) Low power dissipation
b) Small size
c) Good immunity to noise
d) High switching speeds

Explanation: MOS gates do not have high switching speed. They have limited switching capability.

10. CMOS gates are commercially available as which of the following series?

a) 1000
b) 2000
c) 3000
d) 4000

Explanation: CMOS gates are commercially available as 4000 series. This technique is most suitable for commercial circuits.

11. The switching of MOS gates can be improved by using CMOS.
a) True
b) False