Test & Measurement
Multimeters, scopes, meggers — the instruments that find faults
Digital Multimeter (DMM)
Test Instrument
The first instrument anyone buys and the one used every single day: volts, amps, ohms, continuity, diode drop — one rotary dial covers 90% of all fault-finding.
Clamp Meter
Test Instrument
Measures current by clamping around a conductor — no circuit breaking, no fuse risk, works at hundreds of amps. The electrician's daily instrument, built on the magnetic field laws from the textbook.
Insulation Tester (Megger) / Earth Tester
Test Instrument
Applies 250–1000 V DC to measure resistance in megaohms — proving that insulation which reads 'open' on a multimeter actually stays open at working voltage. Plus its sibling, the earth tester that measures how good your ground really is.
Oscilloscope
Test Instrument
Draws voltage against time — the instrument that turns invisible signals into pictures. A multimeter tells you a mystery average; a scope shows the ringing, the noise, the missing pulses and the actual story.
Function / Signal Generator
Test Instrument
Produces known test signals — sine, square, triangle, pulse, arbitrary waveforms — so you can feed a circuit a clean stimulus and watch what it does. The scope's natural partner: one talks, the other listens.
Bench Power Supply
Test Instrument
Adjustable voltage with an adjustable current limit — the current limit is the whole point. Set it just above what the circuit should draw, and your prototype's mistakes cost a red light instead of smoke.
LCR / ESR / Component Tester
Test Instrument
Measures what a multimeter can't: inductance, real capacitance at frequency, and ESR — the equivalent series resistance that reveals a worn-out electrolytic even when its µF still reads fine. The repair bench's lie detector.
Analog Panel Meters (PMMC / Moving Iron / Galvanometer)
Test Instrument
The needle instruments of the Measurements syllabus: the PMMC (D'Arsonval) movement behind every classic ammeter and voltmeter, its moving-iron sibling for AC, and the galvanometer they all descend from. Torque equations, shunts and multipliers — exam bread and butter.
Wattmeter (Dynamometer) & Power Measurement
Test Instrument
Measures real power by multiplying voltage and current inside one instrument: a dynamometer movement whose torque tracks V×I×cosφ. Home of the two-wattmeter method and half the numericals in the Measurements paper.