Logic Gates and Related Devices
109
Table 4.1 (continued).
Type number
Function
Logic family
4050B
Hex noninverting buffer
CMOS
40097B
Tristate hex noninverting buffer
CMOS
40098B
Tristate inverting buffer
CMOS
4069UB
Hex inverter
CMOS
4070B
Quad two-input EX-OR gate
CMOS
4071B
Quad two-input OR gate
CMOS
4081B
Quad two-input AND gate
CMOS
4086B
Four-wide two-input AND-OR-INVERT gate
CMOS
4093B
Quad two-input Schmitt NAND
CMOS
10100
Quad two-input NOR gate with strobe
ECL
10101
Quad two-input OR/NOR gate
ECL
10102
Quad two-input NOR gate
ECL
10103
Quad two-input OR gate
ECL
10104
Quad two-input AND gate
ECL
10113
Quad two-input EX-OR gate
ECL
10114
Triple line receiver
ECL
10115
Quad line Receiver
ECL
10116
Triple Line receiver
ECL
10117
Dual two-wide two- to three-input OR-AND/OR-AND-INVERT gate
ECL
10118
Dual two-wide three-input OR-AND gate
ECL
10123
Triple 4-3-3 input bus driver
10128
Dual bus driver
ECL
10129
Quad bus driver
ECL
10188
Hex buffer with ENABLE
ECL
10192
Quad bus driver
ECL
10194
Dual simultaneous transceiver
ECL
10195
Hex buffer with invert/noninvert control
ECL
Review Questions
1. How do you distinguish between positive and negative logic systems? Prove that an OR gate in a
positive logic system is an AND gate in a negative logic system.
2. Give brief statements that would help one remember the truth table of AND, NAND,
OR, NOR, EX-OR and EX-NOR logic gate functions, irrespective of the number of inputs
used.
3. Why are NAND and NOR gates called universal gates? Justify your answer with the help of
examples.
4. What are Schmitt gates? How does a Schmitt gate overcome the problem of occurrence of an erratic
output for slow varying input transitions?
5. What are logic gates with open collector or open drain outputs? What are the major advantages and
disadvantages of such devices?
6. Draw the circuit symbol and the associated truth table for the following:
(a) a tristate noninverting buffer with an active HIGH ENABLE input;
(b) a tristate inverting buffer with an active LOW ENABLE input;