A voltage tester answers whether voltage is present, while a multimeter tells you how much of it there is along with resistance, current and a spread of other quantities. Most electricians end up carrying both, because the tester is quicker…
True RMS is a measurement method that reports the heating equivalent value of an AC waveform whatever shape that waveform happens to be. It matters because cheaper average responding meters assume a clean sine wave, and on the distorted waveforms…
A CAT rating tells you how much transient energy a test instrument is built to survive, and it always appears as a category paired with a voltage, such as CAT III 600V. The category matters more than the voltage number,…
A digital multimeter measures voltage, resistance and current, and safe use comes down to matching the meter, the leads and the dial setting to the circuit in front of you. The harder truth is that most multimeter incidents are caused…
A UV flashlight is a detection tool, not a light source. It makes certain materials fluoresce so you can find things ordinary white light will not show: pet stains on carpet, refrigerant and coolant leaks traced with UV dye, security…
An IP rating is a two digit code from the international standard IEC 60529, where the first digit describes protection against solids such as dust and the second describes protection against water. On flashlights the numbers you meet most often…
A good everyday carry flashlight is one you actually carry, which puts weight, shape and clip design ahead of peak output on the list of things that matter. In practice that means something under about 5 ounces, with a low…
Almost every flashlight sold today runs on one of four things: a built in lithium cell charged over USB-C, a removable 18650 or 21700 lithium cell, common AA or AAA cells, or a cordless tool battery. Which one suits you…
A lumen measures the total visible light a flashlight puts out, not how far the beam travels or how bright a spot looks at 50 metres. For household jobs, garage work and night walks, 300 to 1000 lumens is enough,…
Choosing a flashlight comes down to three numbers that pull against each other: lumens (total light output), beam distance (how far that light usefully reaches), and runtime (how long the light holds a given output). Decide which of the three…