B.Tech ECE · 4 Units Live · 40 GATE Questions

Control Systems —
Complete Unit-Wise Notes

All 6 units covered in depth — open/closed loop, transfer functions, stability analysis, root locus, Bode plots, and compensators — with GATE PYQs for every topic.

📊 GATE Weightage: 8–12 marks every year — one of the top-scoring subjects
📈 GATE ECE — Control Systems Average Marks per Unit
1–2
Unit 1 · Intro & Block Diagrams
2–3
Unit 2 · Time Response ⭐
2–3
Unit 3 · Stability ⭐
1–2
Unit 4 · Root Locus
2–3
Unit 5 · Frequency Response ⭐
1–2
Unit 6 · Compensators & PID
All Units
Control Systems — 6 Units
UNIT 1
Introduction, Block Diagrams & Signal Flow Graphs
Open-loop vs closed-loop, feedback principles, transfer functions, block diagram algebra, block diagram reduction, signal flow graphs, Mason's gain formula, sensitivity, disturbance rejection
Transfer FunctionBlock DiagramMason's FormulaFeedbackSensitivity
10 GATE Qs
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UNIT 2
Time Response Analysis
First and second order systems, step/impulse/ramp responses, transient specs (rise time, settling time, overshoot, peak time), steady-state error, system type, error constants Kp Kv Ka
1st & 2nd OrderOvershootSettling TimeSteady-State ErrorError Constants
10 GATE Qs
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UNIT 3
Stability & Routh-Hurwitz Criterion
BIBO and asymptotic stability, Routh array construction, zero in first column (ε method), zero row (auxiliary polynomial), range of K for stability, relative stability, gain margin and phase margin introduction
Routh-HurwitzBIBO StabilityRange of KGain MarginPhase Margin
10 GATE Qs
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UNIT 4
Root Locus Method
7 construction rules, starting/ending points, real-axis segments, asymptote angles and centroid, breakaway/break-in points (dK/ds=0), angle of departure, gain at any point on locus, effect of adding poles/zeros
7 RL RulesAsymptotesBreakawayAngle of DepartureGain Calc
10 GATE Qs
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📚 Units 5–6 are being added — check back soon. Only live units are linked above.