GATE IN case studies
GATE IN · Put your knowledge to work in context.
GATE - the Graduate Aptitude Test in Engineering - is a national-level computer-based examination that primarily tests comprehensive understanding of undergraduate-level subjects across Engineering, Technology, Architecture, Science, Commerce, Arts and Humanities. The 2025 edition is organised by IIT Roorkee and conducted by IISc Bengaluru together with seven IITs (Bombay, Delhi, Guwahati, Kanpur, Kharagpur, Madras and Roorkee) on behalf of the National Coordination Board, Department of Higher Education, Ministry of Education, Government of India. The GATE IN case studies are 5 cases and about 3,519 words.
1Thermocouple Loop Whose Reading Tracks Enclosure Temperature
A Type K thermocouple with a grounded measuring junction is installed on a reheat furnace controlled at 900 °C. Type K extension wire runs from the thermocouple head to a 4–20 mA transmitter mounted in a field enclosure on the platform; the transmitter's 24 V loop supply is shared with a variable-frequency-drive cabinet.
756 words, about 4 min2Load Cell Reading Low on a Long Four-Wire Cable
A 50 kN load cell rated at 2.0 mV/V and 350 Ω is bolted under a batching hopper and connected to a weigh indicator 60 m away through 0.1 mm² copper cores (0.17 Ω/m per conductor, two conductors carrying excitation current). The indicator supplies 10 V DC excitation and uses the same supply as its ADC reference, so the measurement is ratiometric.
714 words, about 4 min3Twelve-Bit SAR Front End That Settles Badly After Channel Switching
An eight-channel data-acquisition front end uses a 12-bit SAR ADC with a 5.000 V reference and a 20 MHz conversion clock; a conversion takes 13 clock cycles and the sample-and-hold acquisition window is fixed at 250 ns. Each channel is a piezoelectric accelerometer followed by a charge amplifier whose output resistance is 10 kΩ, then a 400 Ω multiplexer switch and the ADC's 15 pF sampling capacitor.
695 words, about 3 min4Dry-Electrode ECG Front End With 50 Hz Interference
A single-lead ECG front end uses dry electrodes with a 5 kΩ electrode–skin contact mismatch between the two active inputs. The instrumentation amplifier has a differential gain of 1000, an input impedance of 10 MΩ, a CMRR of 80 dB at 50 Hz and an input bias current of 5 nA.
646 words, about 3 min5Level Loop Sawtooth Caused by Valve Hysteresis
A 6 m³ surge tank on a refinery unit has its level controlled by a PI controller (Kc = 2.0, Ti = 4 min, derivative off) driving a 2-inch globe valve whose datasheet hysteresis is 2 % of stroke. In automatic, the level traces a sawtooth: it ramps slowly in one direction for about eight minutes, reverses sharply, and repeats.
708 words, about 4 min