How a digital insightful multimeter works – Principal functions
The digital multimeter is the most used instrumentation device to perform the whole set of measurements and adjustment necessary for the implementation of our electronic projects, as well as for the detection of anomalies during repair and maintenance. The most basic multimeter is capable of performing three basic types of measurements:
- Voltage or voltage in continuous or alternating
- The intensity of continuous or alternate
- Measurement of resistance and continuity
These basic measures are usually incorporated in other more complete models, capacitor capacity measurements, frequency counter, transistor and diode check etc.
Observing the digital multimeter we can distinguish the following parts:
Selection of functions: Normally it is formed by a switch in the form of a roulette or button where we can turn to select the function
Digital display: Where we see the function, selected range and value of the measure.
Connection terminals: Here we connect the test leads, paying special attention not to make mistakes depending on the magnitude to be measured.
Test leads or hoses and other accessories (temperature probes, crocodile clips …) the digital multimeter has batteries or batteries inside for its operation and many times you have to remove some screws for replacement. It also has fuses inside that protect the multimeter from surges and intensities not suitable for it. As you can see the multimeter is an essential element in any laboratory whether professional or for the amateur because with him we can find out and check data in the assembly of our prototypes and not go “blind”.
The first issue we want to address when buying a digital multimeter is security. It is a very important issue that is almost always related to the cost of it. Depending on our needs and the use we are going to give the multimeter, we will need to buy a digital multimeter whose security measures are in accordance with the magnitudes to be measured and under what conditions we will use it.
When we are going to buy an insightful multimeter we will see that its price becomes more expensive due to the precision, range of measurement and, above all, the safety it gives us when we have to use it to measure tensions and high consumption in which an error could have bad consequences. For further information, have a look at the insightful multimeter tips. It is clear that saving insecurity is not a good idea…
This type of digital multimeters can only be used in very limited conditions of low power electronics, but of course, as we progress in our knowledge, we will do more advanced projects and one day we will want to check if there is voltage in a 220V outlet, no? The smartest thing is to buy a quality digital multimeter that will last us for many years. There is no need to buy a € 500 Fluke if we are not industrial electricity professionals. There are good multimeters in the range of 50 – 80 € but you have to know what you are buying and if it is suitable for your measurement needs. Our recommendation is that you invest a little more in this measuring instrument for your safety because if one day we put the tips wrong when measuring, we can have a serious dislike. Check out the insightful multimeter tips.
As the multimeter will be used in low power electronics, we will handle voltages that will not normally exceed 30V and a maximum consumption of 5A. Even so, our multimeter will have to have some security measures and it will have to be built with a minimum of quality so that it lasts a long time. When buying your digital multimeter, look for one that has a good internal construction, ideally with double insulation and that incorporates ceramic fuses (not glass). For queries see insightful multimeter tips.
A very important thing is that you have a fuse at the entrance to measure intensities of 10A , the video you saw at the beginning of this post is an example of what would happen if you do not have it or have a glass that would not be effective to cut the arc that would be formed when shorting. It usually comes screened in the case when it is not worn with the unfused warning and the maximum allowable current, as you can see, this digital multimeter incorporates the necessary security measures.
Whenever we are going to use the digital multimeter, we will have to be clear about the type of magnitude we are going to measure. In this case, the voltage can be alternating (AC) or continuous (DC). If it is alternate, we will select it with the blue button, until AC shows on the display. To measure DC-DC voltages we do not need to press anything since it is the default selection when turning on the multimeter. We will start at the position of the selector in V since it is the highest (we do not know the value to be measured). There is another position on the selector (mV) for precision measurements of very small voltages.
- Now we will connect the test leads to the multimeter paying attention to do it in the right place.
- Insert the black banana in COM and the red in V and we can use the tips in the place to be measured.
- We will see that it gives us the reading both on the display and in the analog bar simultaneously.
This bar is updated much faster about 30 times per second with respect to the digits of the display (4 / s), so we can see voltage fluctuations that with digits would be impossible. There are multimeters that also have the analog bar, but being of poor quality they do not have update speed and the bar does not help. We have a position in the selector (mV) to measure small voltages, range of 220 mV with a resolution of 0.01mV and accuracy of the order of 0.8%. This position of the selector gives us a very high input impedance of about 3000MΩ, much better to measure such small voltages with precision.
This is the most common way to act when measuring because except to measure intensities, we will place the red tip in one of the other 2 terminals, normally as we have it now we can measure everything else. In the case of alternate voltages, we press the blue button until AC appears on the display. If we want to measure the frequency of the voltage we are measuring, we will press the yellow button and it will appear on the display. Pressing again we will return to the voltage measurement. Still worried? test out insightful multimeter tips.