What is the Best Multimeter – 5 Key Factors?
The first step when determining what is the best multimeter is to ask yourself some key questions:
- What are you trying to measure?
- Where are you working (i.e. industrial power, hobby electronics, medical devices)?
- Are there any special tests or functions you will need?
- What is your budget?
- What is your experience and knowledge with electronics?
Consequently, selecting the right multimeter is a balancing act between what you need, what you want, and how much you are willing to spend to get a meter. Therefore, in order to select the right multimeter you need to know the:
- Difference between an autoranging and manual ranging meter
- Types of multimeter functions
- Value of a true RMS meters
- Impact of multimeter specifications
- Physical design considerations for purchasing a multimeter
Therefore, consider watching the video below to learn about these 5 key multimeter considerations.
Multimeter: Auto-Ranging vs Manual Ranging
First off, I would never recommend buying an manual ranging meter! Currently, in todays market you can get an affordable auto-ranging meter for just a little bit more money and save yourself tons of time. Manuel ranging meters require you to select the approximate range for voltage, resistance, and current.
In contrast, auto ranging meters require you to select the function only (i.e. dc voltage, ac voltage, resistance, current).
Therefore auto-ranging meters are always easier to use and require less knowledge of the circuit or component being measured. The only negative of a auto-ranging meter is that it can take extra time to read a measurement as the meter cycles through the different ranging automatically. However, the amount of time is usually quite small and negligible for most cases.
First, it is a good idea to know what types of functions you want on your multimeter before you purchase a new meter. Furthermore, here is a list of common and uncommon functions
Common Multimeter Functions
- Voltage – ideally with a range of mV to 1000 V
- Resistance – ideally with a range of 1- 20 MOhms
- Current – measures amps and mA, may need uA for small electronics signals
- Continuity – ability to check for a low resistance path
Less Common Multimeter Functions
- Diode measurement – will vary in the max text voltage (a good voltage range is up to 4 V for testing LED’s
- Transistor Testing – not important don’t need it, its a gimmick
- Temperature/thermocouple – nice if you work with HVAC
- Capacitance – try to get one that can measure single digit nF range
- Frequency – not so essential – but if you want this function make sure you get a high enough range ideally in the MHz range
True RMS vs Non True RMS Multimeters
Next let talk about true RMS vs non true RMS meters. The distinction between a true RMS meter and a non RMS meter only matters for AC waveforms. Therefore, if you only use your meter for dc circuits true rms meters will have little to no value. A non true RMS meter assumes a perfectly sinusoidal waveform for the input signal. If there is a square wave or other waveform (for example a large DC offset square wave) then your meter will not read the correct voltage. The reading on your non true RMS meter can be tens of percent off depending on the waveform. In conclusion if you are going to be measuring any AC voltages I recommend you get a true RMS meter.
Ranges, Counts, and Accuracy
In addition to what we have discussed so far you should be aware of the specifications of your meter. The specification of your meter will list information such as the ranges the meter is capable of, the counts of the meter, and the accuracy of the meter.
Your multimeter ranges tell you what the meter can measure. So if your meter measures 1-1000V you can not (or at least should not) use your meter to measure a 10kV source.
Your multimeter counts tells you how many digits the meter will display. A 2000 count meter can display digits from 0000 to 1999 and have 4 digitis but as soon as the meter goes above 2 in the first digit you will only be able to display 3 digits in the display. Therefore if you measure a 4 volt source with a 2000 count meter you will be able to display 4.## for a total of 3 digits. However if you measured a 1 volt source you would be able to display 2.### for a total of 4 digits.
This can be a little dense at first and I recommend watching the multimeter counts video below if you are interested in learning more.
In general, I recommend at least a 6000 count meter. However, if you are doing industrial applications you may want a meter with a much higher count value.
Moreover, you want to consider the physical design of you meter including: How rugged do you need the meter to be, what type of probes do you prefer to use (i.e. shrouded, unshrouded, clips). What size screen do you want and how much information gets displayed. Can the fuses and batteries be easily replaced?
Here are some of our recommendations for meters
- Best Budget Meter Klein tools multimeter – https://amzn.to/3FjjtFm
- Best Pro Meters – Fluke 77-IV Digital Multimeter https://amzn.to/3rIjg95
- Best for Electricians and HVAC – https://amzn.to/3lGw6RT
- Data Logging Meter – https://amzn.to/3llE6HN
Want to learn more about electronics!
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