Learn about Digital Decoders with interactive circuit diagrams, truth tables, Boolean expressions, decoding logic, logic gate implementation, and digital logic examples.
A decoder does the opposite of an encoder: it takes a binary code and activates exactly one of several output lines. With two select inputs A1A0, the decoder drives one of four outputs D0–D3 high (one-hot) — D0 = A1'A0', D1 = A1'A0, D2 = A1A0', D3 = A1A0. Each output needs an inverted copy of its inputs before the AND gate, so this is a two gate delay circuit (NOT, then AND).
| A1 | A0 | D3 | D2 | D1 | D0 |
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