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Question
You are given two circuits as shown in following figure, which consist of NAND gates. Identify the logic operation carried out by the two circuits.
(a)
(b)
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Solution
In both the given circuits, A and B are the inputs and Y is the output.
a) The output of the left NAND gate will be `bar("A"."B")`, as shown in the following figure.
Hence, the output of the combination of the two NAND gates is given as:
`"Y" = bar((bar("A.B")).(bar("A.B")))= bar(bar("AB")) + bar(bar("AB")) = "AB"`
Hence, this circuit functions as an AND gate.
(b) `bar"A"` is the output of the upper left of the NAND gate and `bar"B"` is the output of the lower half of the NAND gate, as shown in the following figure.
Hence, the output of the combination of the NAND gates will be given as:
`"Y" = bar"A".bar"B" = bar(bar"A") + bar(bar"B") = "A"+"B"`
Hence, this circuit functions as an OR gate.
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Useful Constants and Relations:
| 1. | Charge of a proton | (e) | =1.6 × 10-19C |
| 2. | Planck's constant | (h) | = 6·6 × 10-34 Js |
| 3. | Mass of an electron | (m) | = 9·1× 10-31 kg |
| 4. | Permittivity of vacuum | (∈0) | =8 · 85 × 10-12 Fm-1 |
| 5. | `(1/(4pi∈_0))` | =9 ×109 mF-1 | |
| 6. | Permeability of vacuum | (μ0) | = 4π × 10-7 Hm-1 |
| 7. | `((mu_0)/(4pi))` | =1 × 10-7 Hm-1 | |
| 8. | Speed of light in vacuum | (c) | = 3× 108 ms-1 |
| 9. | Unified atomic mass unit | (u) |
= 931 MeV |
| 10. | Electron volt | (leV) | = 1.6 × 10-19 J |
With the help of a diagram, show how you can use several NAND gates to obtain an OR gate.
Useful Constants and Relations :
| 1. Speed of Light in Vacuum | (c) = 3.00 x 108 m/s |
| 2. Charge of a proton | (e) = 1.60 x 10-19C |
| 3. Planck's Constant | (h) = 6.6 x 10-34 Js |
| 4. Permeability of vacuum | (μ0) = 4π x 10-7 Hm-1 |
| 5. Electron Volt | (1eV ) = 1.6 x 10 |
| 6. Unified Atomic Mass Unit | (1u) = 931 MeV |
| (π) = 3.14 | |
| ( ln 2 ) = 0.693 |
NAND and NOR gates are called universal gates primarily because they ______.
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Write the truth table for the circuit shown in figure. Name the gate that the circuit resembles.
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A logic gate circuit has two inputs A and B and output Y. The voltage waveforms of A, B and Y are shown below.
The logic gate circuit is ______.
Which of the following gives a reversible operation?
