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These notes take you from absolute zero to full marks in GATE Digital Logic. Phase 0 starts with what a bit is and how we count with only 0 and 1, so nothing is assumed. Read in order: every lesson uses only ideas taught before it. Each lesson takes 35–55 minutes. Every lesson has the same sections. Questions always come before answers. Answers sit in a closed Answer Vault at the bottom of each lesson; the Predict First answer opens Section 3.
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Super-easy promise. Every Core Concept begins with an In plain words box: the whole idea in everyday language (light switches, odometers, a railway signal box) before any jargon. New terms are explained the first time they appear.
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Verified. Computable answers were re-computed by code before they were written down: base conversions, two's-complement values, IEEE 754 bit patterns, truth tables, prime implicants and minimal forms, circuit outputs, counter sequences and state machines.
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Spaced recall
Each lesson opens with 3 warm-up questions on earlier lessons: usually one from the lesson just before and the others from further back, so older ideas keep coming back. Answer them in your head first.
Your commands, on this page
| Command | Here |
|---|---|
| next | The “Type next →” link at the end of every lesson. |
| roadmap | The roadmap below and the sidebar. Press Mark as done on a lesson and it gets a ✅ in both (stored in this browser). |
| revise [lesson ID] | Search the sidebar for the ID, or use that lesson's Rule Card and the Master Rule Sheet (7.1.1). |
| simpler / deeper | Ask Claude in chat, naming the lesson ID. Deeper practice for every chapter is in its Lock-in and in Phase 7. |
| start final test | Lesson 7.4.1. The test page shows no answers. |
| submit | Enter your answers in 7.4.1 and press Submit answers: score with GATE negative marking, topic-wise accuracy, the questions you got wrong and the lessons to re-read. |
| key | The very last section of the notes. |
Conventions used throughout
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- Numbers: a subscript gives the base, e.g. (1011)₂ or 1011₂; numbers without one are decimal. Hexadecimal may also be written with 0x (0x2F).
- Signed numbers are in 2's complement unless a question says otherwise.
- Boolean notation: A' is NOT A, AB (or A·B) is AND, A + B is OR, A ⊕ B is XOR.
- Minterm numbering: the first variable is the most significant bit. For F(A, B, C, D), minterm 13 = 1101 = A B C' D.
- K-maps list rows and columns in Gray-code order 00, 01, 11, 10.
- Floating point means IEEE 754 single precision (1 sign bit, 8 exponent bits with bias 127, 23 fraction bits) unless a question gives another format.
- Flip-flops are positive-edge-triggered unless stated; delays are in nanoseconds (ns).
- Marks follow GATE: MCQ wrong answers cost 1/3 (1-mark) or 2/3 (2-mark); MSQ and NAT have no negative marking; MSQ has no partial credit.