Digital multimeters are essential for most of the electrician’s work. The device is very much useful for testing, troubleshooting and repairing troubles. It can also be used for the installation of electrical equipment.
Picking the right one is hard for there is a wide variety of multimeter on the market. Before buying multimeters, you have to make sure that the device is suitable for your needs, applications, your budget and how often you’re going to use the tool. However, in order to have the best, you have to consider a lot of things more than these. Remember that with a multimeter, you will be dealing with dangerous electrical circuits and many other life-threatening electrical hazards.
For more information about using multimeters in a safe way, click here.
What to Consider
One of the most important things to be considered before buying any kind of multimeter is its accuracy. The accuracy of the device is the highest allowed error limit for readings and is usually expressed through this symbol: ± (as a calculation of % of reading plus the number of least significant digit or LSD). The calculation will show the specifications of accuracy as the maximum limit around the value of the signal is measured.
The LSD represents different errors such as offset noise and analog-digital converter tolerances.
2. Resolution and Digits
The smallest change in an input signal that generates a change in the output signal is defined as a resolution. Digital multimeter’s resolution is used to be expressed by the number of digits it can display. If you have a 3 ½ digital multimeter, it has 3 full digits that can display 0 to 9 values but sometimes can either be 0 or 1. Commonly, digital multimeters are either 3 ½ or 4 ½ digit meter with a display range that falls at of ±1,999 or ±19,999.
There are many specifications of resolution. Generally, it is specified as the count which refers to a number that a meter can display right before it has changed the range of the measurements.
3. Input Impedance
Input impedance refers to the value of impedance between the input test jacks of an electrical test device when it is used to make measurements for voltage. Input impedance has two categories. First, the low impedance and the second one is the high impedance. “Z” is the symbol used for impedance and its two categories are also called as the Low Z and the High-Z. The input impedance of the most circuit is high causing the measurement of the multimeters not affect the circuit’s operation and will not negatively influence the readings.
When measuring highly sensitive electronics, make sure to choose a device with high input impedance to ensure that the accuracy of the measurement is achieved.
4. True RMS Converter
When measuring the value of an alternating current signal, it is often important to convert the signal into a direct current signal. Such conversion is known as the root mean square (RMS) value and most low-cost instruments, as well as signal converters, used this conversion by filtering the signal into an average rectified value. The application of a correction factor can help this process better at the same time.
There are commonly two types of multimeter’s response: average responding and true RMS. The value of the true RMS is not just the average of the complete value of the curve but works with sinusoidal waveforms as well. However, this will not going to work well for more complex nonlinear waveforms. For more expensive multimeters, you can have RMS feature which is essential for more complex calculations.
Before buying multimeters, there are many things you need to consider. Things and factors that have been mentioned above are just some of them. So, in every crucial purchase decision, you would make, make sure that what you get is the right device you really need. In case there are still some troubles in your mind, the founder of zoniv.com will be glad to help you anytime.
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