Multimeters can be complex to understand if you’re new to the subject. There are some important features that all good multimeters should incorporate in them. Only then they’d be worthwhile. Here we’ll briefly discuss them but in laymen’s terms.
Safety Rating: Whenever you work with electronics and electricity, the first point is about ensuring safety. And when testing AC cycles, multimeters operate by connecting with the bare wire through probes.
So, to make sure you and your devices are safe, multimeters need to be certified to handle certain types of loads. And to do that, there are some ratings such as CAT. There are 4 categories of CAT rating.
- CAT I
- CAT II
- CAT III
- CAT IV
The first two categories are taken as the weakest category as they cannot take much power, and most of them can’t work with AC. Then, in the CAT III category, there are different divisions depending on voltage.
The divisions are 300V, 600V, 1000V, etc. And the same is with the CAT IV category, and this category is the highest level of safety.
There are other certifications regarding electric safety standards such as IEC, International Electrotechnical Commission.
Measurement Accuracy and Readability: Getting an accurate reading and being able to read the reading is vital. A good backlit panel will suffice you for that. And the most accurate measurement method is the True RMS method. What’s True RMS?
RMS vs TRMS: RMS = Root Mean Squared is a method of measuring the average value of AC/DC cycles. Multimeters take the peak value from multiple readings and multiply it by a reduction factor to get an average value.
For currents, it’s a sine wave. This is called the Root Mean Squared method.
Whereas in the modern True RMS method, the multimeter takes multiple measurements in the AC cycle and averages them in a geometric mean formula to get an average value. This gives a more accurate final reading.
Clamp Meter: Clamp multimeters can be lifesavers both metaphorically and literally. With this type of multimeter, you can measure and read all basic readings without having to come in contact with naked wires because there is no need to strip of plastic coating on the wire.
Just clamp the wire, and it’ll give you reading. It’s such a nice feature for all beginners.
Low Z vs High Z: Impedance(Z) is like resistance, but it also considers the capacitance and inductance of the circuit. It’s a measure of opposition to the current circuit.
Having a low Z or low impedance in a multimeter is important to avoid ghost voltages messing up the reading. Ghost voltages are created by induction from surrounding power sources, that can show effect so much that a wire without a current will show a voltage reading.
So, for a more accurate reading, you need Low Z in multimeters, and the Fluke 117 proved to be the best Low-Z multimeter.
Auto-Ranging: Finding the current reading of any measurement can be tough when you have to manually select the range of measurement. It takes a lot of trial and error, whereas if the multimeter has the automatic ranging capability, it can find out the range automatically. And that makes the process faster and easier.
Other Features: The features above are the must-have features that all multimeters should have. But there are features like continuity and diode check, capacitance, and temperature measurement that can come in handy.
