GATE 2026 Syllabus for IN

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IN Instrumentation Engineering

Section 1: Engineering Mathematics
Linear Algebra: Matrix algebra, systems of linear equations, consistency and rank,
Eigenvalue and Eigenvectors.
Calculus: Mean value theorems, theorems of integral calculus, partial derivatives, maxima
and minima, multiple integrals, Fourier series, vector identities, line, surface and volume
integrals, Stokes, Gauss and Green’s theorems.
Differential Equations: First order equation (linear and nonlinear), second order linear
differential equations with constant coefficients, method of variation of parameters,
Cauchy’s and Euler’s equations, initial and boundary value problems, solution of partial
differential equations: variable separable method.
Analysis of Complex Variables: Analytic functions, Cauchy’s integral theorem and integral
formula, Taylor’s and Laurent’s series, residue theorem, solution of integrals.
Probability and Statistics: Sampling theorems, conditional probability, mean, median,
mode, standard deviation and variance; random variables: discrete and continuous
distributions: normal, Poisson and binomial distributions.
Numerical Methods: Matrix inversion, solutions of non-linear algebraic equations, iterative
methods for solving differential equations, numerical integration, regression and correlation
analysis.
Section 2: Electricity and Magnetism
Coulomb's Law, Electric Field Intensity, Electric Flux Density, Gauss's Law, Divergence,
Electric field and potential due to point, line, plane and spherical charge distributions, Effect
of dielectric medium, Capacitance of simple configurations, Biot‐Savart’s law, Ampere’s
law, Curl, Faraday’s law, Lorentz force, Inductance, Magnetomotive force, Reluctance,
Magnetic circuits, Self and Mutual inductance of simple configurations.
Section 3: Electrical Circuits and Machines
Voltage and Current Sources: Independent, dependent, ideal and practical; v-i relationships
of resistor, inductor, mutual inductance and capacitor; transient analysis of RLC circuits
with dc excitation.
Kirchoff’s laws, mesh and nodal analysis, superposition, Thevenin, Norton, maximum power
transfer and reciprocity theorems.
Peak-, average- and rms values of AC quantities; apparent-, active- and reactive powers;
phasor analysis, impedance and admittance; series and parallel resonance, locus
diagrams, realization of basic filters with R, L and C elements. transient analysis of RLC
circuits with ac excitation.
One-port and two-port networks, driving point impedance and admittance, open-, and short
circuit parameters.
Single Phase Transformer: Equivalent circuit, phasor diagram, open circuit and short
circuit tests, regulation and efficiency; Three phase induction motors: principle of operation,
types, performance, torque-speed characteristics, no-load and blocked rotor tests,

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equivalent circuit, starting and speed control; Types of losses and efficiency
calculations of electric machines.
Section 4: Signals and Systems
Periodic, aperiodic and impulse signals; Laplace, Fourier and z-transforms; transfer
function, frequency response of first and second order linear time invariant systems,
impulse response of systems; convolution, correlation. Discrete time system: impulse
response, frequency response, pulse transfer function; DFT and FFT; basics of IIR and FIR
filters.
Section 5: Control Systems
Feedback principles, signal flow graphs, transient response, steady-state-errors, Bode
plot, phase and gain margins, Routh and Nyquist criteria, root loci, design of lead, lag and lead-
lag compensators, state-space representation of systems; time-delay systems;
mechanical, hydraulic and pneumatic system components, synchro pair, servo and stepper
motors, servo valves; on-off, P, PI, PID, cascade, feed forward, and ratio controllers, tuning of
PID controllers and sizing of control valves.
Section 6: Analog Electronics
Characteristics and applications of diode, Zener diode, BJT and MOSFET; small signal
analysis of transistor circuits, feedback amplifiers. Characteristics of ideal and practical
operational amplifiers; applications of opamps: adder, subtractor, integrator, differentiator,
difference amplifier, instrumentation amplifier, precision rectifier, active filters, oscillators,
signal generators, voltage controlled oscillators and phase locked loop, sources and effects
of noise and interference in electronic circuits.
Section 7: Digital Electronics
Combinational logic circuits, minimization of Boolean functions. IC families: TTL and CMOS.
Arithmetic circuits, comparators, Schmitt trigger, multi-vibrators, sequential circuits,
flipflops, shift registers, timers and counters; sample-and-hold circuit, multiplexer, analog-
to-digital (successive approximation, integrating, flash and sigma-delta) and digital-to-
analog converters (weighted R, R-2R ladder and current steering logic). Characteristics of
ADC and DAC (resolution, quantization, significant bits, conversion/settling time); basics of
number systems, Embedded Systems: Microprocessor and microcontroller applications,
memory and input-output interfacing; basics of data acquisition systems, basics of
distributed control systems (DCS) and programmable logic controllers (PLC).
Section 8: Measurements
SI units, standards (R, L, C, voltage, current and frequency), systematic and random errors
in measurement, expression of uncertainty - accuracy and precision, propagation of errors,
linear and weighted regression. Bridges: Wheatstone, Kelvin, Megohm, Maxwell, Anderson,
Schering and Wien for measurement of R, L, C and frequency, Q-meter. Measurement of
voltage, current and power in single and three phase circuits; ac and dc current probes; true
rms meters, voltage and current scaling, instrument transformers, timer/counter, time,
phase and frequency measurements, digital voltmeter, digital multimeter; oscilloscope,
shielding and grounding.
Section 9: Sensors and Industrial Instrumentation
Resistive-, capacitive-, inductive-, piezoelectric-, Hall effect sensors and associated signal

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conditioning circuits; transducers for industrial instrumentation: displacement (linear and
angular), velocity, acceleration, force, torque, vibration, shock, pressure (including low
pressure), flow (variable head, variable area, electromagnetic, ultrasonic, turbine and open
channel flow meters) temperature (thermocouple, bolometer, RTD (3/4 wire), thermistor,
pyrometer and semiconductor); liquid level, pH, conductivity and viscosity measurement.
4- 20 mA two-wire transmitter.
Section 10: Communication and Optical Instrumentation
Amplitude- and frequency modulation and demodulation; Shannon's sampling theorem,
pulse code modulation; frequency and time division multiplexing, amplitude-, phase-,
frequency-, quadrature amplitude, pulse shift keying for digital modulation; optical sources
and detectors: LED, laser, photo-diode, light dependent resistor, square law detectors and
their characteristics; interferometer: applications in metrology; basics of fiber optic sensing.
UV-VIS Spectrophotometers, Mass spectrometer.