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Question
You are given a circuit as shown in the figure, which consists of the NAND gate. Identify the logic operation carried out by the two. Write the truth table. Identify the gates equivalent to the tow circuit.

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Solution

`"Y"_1 = bar"A.A" = bar"A"`
`"Y"_2 = bar"B.B" = bar"B"`
`"Y" = bar("Y"_1."Y"_2) = overline(bar"A".bar"B") = overlineoverline(A) + overlineoverline(B) = "A" + "B"`
The equivalent gate is OR gate
Truth table
| A | B | Y1 | Y2 | Y |
| 0 | 0 | 1 | 1 | 0 |
| 0 | 1 | 1 | 0 | 1 |
| 1 | 0 | 0 | 1 | 1 |
| 1 | 1 | 0 | 0 | 1 |
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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 |
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| 8. | Speed of light in vacuum | (c) | = 3× 108 ms-1 |
| 9. | Unified atomic mass unit | (u) |
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| 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 |
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