Guide to buying multimeters
Today multimeters are devices that are used frequently. Therefore, there are many brands available , which makes selecting a model difficult. The general recommendation is to consider the opinion of other users and look for properties that denote quality and functionality. To make the choice easier, we have put together a guide to buying the best multimeter on the market.
If you want to know how much a multimeter costs, it is necessary to analyze the precision capacity of the data that the device gives about the current measurement in the different forms and units. In general, devices with a low margin of error and a high degree of reliability and data accuracy tend to be more expensive.
This precision is usually given by the quality of the sensors built into the multimeter mechanism. It is recommended that equipment with a high degree of precision be acquired, so that there are no errors in the data and that the work and measurements can be done correctly.
When buying one of these equipment it is important to make a comparison of multimeters based on the type or operating mode of the device. On the market there are analog multimeters and digital multimeters. Both modalities serve the same purpose. For one thing, analogs are older and are the basis for digital models. Its price tends to be cheaper and its weight is light. However, according to the consideration of some experts, these models are impractical and with a low level of precision.
Meanwhile, digital multimeters are devices that include the possibility of multiple functions with respect to measurement, being equipment with a high degree of reliability, which display data on a screen. In addition, they are innovative and easy-to-use alternatives.
In case the selected model is digital, it must have a screen. Many want to get a cheap multimeter, but beyond the price, it is important to analyze the screen, its dimensions and the information that can be displayed on it.
It is recommended to purchase models that are equipped with a large screen, which allows you to see the collected figures clearly. Most models incorporate displays with LED technology and white light, as well as a backlight system and a rear torch that works to illuminate dark areas.
When selecting an alternative it is important to look at the design that the manufacturer devised for the model in question. Regarding the design, it is more than an aesthetic matter, since it is necessary that these devices have a design with light, compact and practical properties that facilitate their handling for the work to be successful. It should also be comfortable to hold.
On the other hand, in relation to design, there are models that incorporate rear supports, so that the multimeter can be held on a flat surface and many others are equipped with magnets that allow it to be attached to metal elements, giving the user the possibility of having hands free.
There are models of basic multimeters and many others that offer the user a wide measurement system, these being professional style. The most popular models on the market are equipped with the ability to measure much more than current.
With these devices you can measure voltage, alternating and direct currents, diode tests, resistance, frequency, temperature, capacitance, high pressure, continuity, sensitivity, relative value measurement, and duty cycle tests can be done. According to the range, the multimeter will have more or less functions.
When working with electricity it is of the utmost importance that care is taken, because any mistake could lead to serious injury to the user or a short circuit. To reduce the chances of accidents, it is appropriate to look for alternatives that have a high level of safety. For example, some designs are endowed with the property of automatic shutdown, overload protection, and current input fuse protection, rated for the circuit being operated. Otherwise, it is best to avoid high voltage circuits.
In addition, there are models that have a polarity indicator and on-screen data retention. In the first case, it is a protection function against reverse polarity, which prevents a short in the event of human error. In the second, there is the possibility of keeping the data on the screen by pressing a button.
Frequently asked questions
Q1: What should an automotive multimeter have?
There are different types of multimeters. However, they may not all be suitable for certain purposes. As a general rule, it is convenient that they have basic functions for automotive. So when selecting an alternative, it is important to opt for those multimeter options of quality and medium measurement range, with a high degree of reliability or precision in the results obtained. In addition, it must have an input fuse to measure currents of 10 A.
Q2: How to measure the voltage with multimeter?
To measure the voltage of the current it is necessary to previously disconnect the electrical supply to the circuit. Then, the solders should be removed from the circuit, in order to have the space to insert the multimeter probes. At this point, you must select whether it is direct current (DC) or alternating current (AC). To continue, you need to connect the black wire to the COM input and the red wire to the amp input. Next, the ends of the cables must be connected to the circuit, so that the current goes through the multimeter. Then it is necessary to activate the circuit and rescue the data thrown, considering the unit of measurement.
Q3: What is the multimeter with recording device for?
As its name implies, the loggers seek to keep track of electrical activity, through the collection of data automatically 24 hours a day, as a kind of monitoring, in order to have a better impression of electrical activity , giving an accurate view on the conditions. In multimeters they have different purposes, but the intention is to be able to program and analyze the variables to know problems in the supply of electric current.
Q4: What should a multimeter have that measures temperature?
Multimeters have different functions and according to these, as well as the precision of the device, they tend to be more expensive or cheaper. Among the functions, professional type multimeters even have the ability to measure temperature. This is possible thanks to the fact that the device is equipped with special sensors to obtain the ambient temperature, without the need to add other equipment. In general, it should be turned towards the degree or Fahrenheit measurement and after a few seconds the data will appear on the screen.
Q5: Which is better, the analog or digital multimeter?
Both models of multimeters are suitable for measuring current. However, some considerations point towards the fact that digital alternatives tend to be more robust and accurate in data collection. For their part, the analog models do not have a digital number display, but the results are displayed with indicator arrows and are old models. These tend to be lighter, easier to operate, and cheaper. But in relation to functionality, we conclude that it is appropriate to have a digital model.
Q6: Where to repair the multimeter?
Sometimes these measuring devices tend to break down, requiring repair. However, before going to a technician, you can check the device’s protection fuse. Many brands include technical assistance, so you should review the warranty and go for it if it is within the time. In the case of low-cost multimeters, they tend to be disposable AND a repair could cost more than buying new equipment.
Q7: When was the multimeter invented?
The multimeter hit the market in 1923, so it was created a couple of years earlier. It arose in response to the need to unify the functions of three devices, the ammeter, the voltmeter and the ohmmeter in one, to simplify the work. His invention is conferred on the engineer Donald MacAdie and was called Avo. In its beginnings, it was a device for direct current circuits. Over the years, new functions were added, making it possible to measure alternating current. Later, the digital prototypes, whose base of operation is the same as the analog ones, came onto the market. However, they do include other functions for electrical troubleshooting.
Q8: Why doesn’t my multimeter sound?
There may be a number of reasons why the multimeter does not sound. One of them may be that it does not have this option within its functions or that this property is damaged. Another simpler reason may be due to the fact that the measurement is in direct current. The hum usually begins when continuity is measured with values between 0 and 10 ohms. In the 2K resistors there are more ohms and it will not sound.
How to use a multimeter
A multimeter is a piece of equipment that is used to measure current and is usually a widely used device today. Due to the fact of having contact with electric current, great care must be taken in handling. Here we will give you some guidelines to properly use a multimeter.
Identify the multimeter
Before starting to measure it is necessary to check what type of multimeter you will use, whether digital or analog. Next, it is necessary to identify the kind of measurement that will be carried out , whether it is intensities or resistances.
Read the manual carefully
Before starting to work with a multimeter, it is important to read the manual and know the maximum voltage capacity, as well as the specifications of the equipment to avoid accidents.
By turning the knob, which is usually in the middle of the device, a function can be selected according to what is to be measured, such as temperature, direct voltages, alternating voltage, alternating current amperage, resistance, or others.
Connect the probes
For this step it is necessary to be careful and connect the probes correctly: the black one in the general socket and the red one in the socket to measure the voltage. Next, the other side of the probe should be connected to the object. Some models are able to show if there is reversed polarity and in this case the cable entry must be changed.
Measures alternating and other voltages
In the case of measurement for alternating voltages, the knob must be placed on the measurement of alternating voltage and the probes at the points of the current socket. The same action must be carried out for the rest of the measurements that the device has available within its functions.
This step can be more complex. First, it is necessary to place the multimeter in currents with the rotating wheel. Next, the circuit must be opened to locate the terminal of the red wire and the current to pass through the tester.
Disconnect the resistor
Disconnect the electrical power supply to the circuit. Remove the solder so that you can insert the probes of the multimeter leads.
Select the type of current and connect the probes
On the multimeter, set the type of current to be tested whether it is alternating current or direct current. Next, it is necessary to connect the black probe to the COM input of the multimeter, while the red wire must be connected to the input of the multimeter which is called amps. Then it is necessary to connect the other side of the wire in the circuit so that the current can flow and enter the multimeter in order to output the data. For the energy to come into contact with the wires and pass to the multimeter, it is necessary to reactivate the circuit.
Read the measurement
On the device screen you will see some values that correspond to the measurement that has just been made . Record these data and remember to consider the unit of measurement.
When working with electricity it is necessary to be careful and pay attention to the type of measurement that is carried out. Avoid connecting test leads to current inputs and making a voltage measurement. This can cause a short, as well as damage to the circuit being measured, the multimeter, and the user.
What can you measure in your car with a multimeter?
The multimeter is a versatile tool, with which to perform all kinds of electrical measurements. Something that is quite useful in our vehicle, as it helps when looking for faults or breakdowns in its components.
Although a car is essentially a mechanical vehicle, the truth is that it also has a fundamental electronic part. From starters to power windows to a host of car accessories, they all rely on electricity. All this without forgetting the battery, which is responsible for storing all the vehicle’s energy, which is obtained through the alternator.
All these systems require some control and periodic verifications, in which having the best multimeter can be of great help. It is true that we are not talking about something that is available to all users, but they are easy measurements to perform if we have the right tool and knowledge. To give you an idea of the usefulness of this product, we leave you some of the most frequent uses that it has in the car.
Traditionally, the use of the multimeter to measure the battery voltage has been the most common that has been given to the device. Something that allows estimating the state of charge of the battery and its capacity, being useful to assess if it is really necessary to change said battery or if we can keep it for a longer time.
The measurement process is as simple as placing the test rods on the battery terminals, starting with the black rod, which is placed on the negative terminal. The red cable, for its part, will be placed on the positive terminal. At the moment, we will have the measurement on screen. If this measurement shows values above 12.5 volts of charge, then the battery is in good health. But if the battery is below 12.2 volts, then you will have to charge it and even think about replacing it.
Checking the ignition system
All systems that manage ignition require electrical current to function. From the starter plug to the ignition coil, not forgetting the corresponding voltage regulators.
All these elements can also be verified with a multimeter, in order to evaluate if they comply with the expected parameters within the normal operation of the vehicle. As a reference, in the case of the ignition coil, we can measure the electrical resistance it offers at the time of ignition, which can vary from 0.3 to 1 ohm for electronic ignition coils, increasing that range to 3 to 5 ohms for the ignition switches.
Regarding the spark plugs, this element makes it possible to measure the intensity of the electrical charge that they develop when igniting the air-fuel mixture. In the event of a spark plug failure, it is always advisable to check that the electrical wiring is supplying power correctly, in addition to checking that the condition of the spark plug itself is adequate. However, in the event of failure, this is an economic problem to solve.
As for the regulator, the multimeter allows us to verify that it is adequately fulfilling its mission, so that we do not perceive large voltage variations in the system when the vehicle is turned on or when the vehicle is operating. In both cases, it is convenient to carry out measurements on the input and output elements of that regulator, to check that the voltage varies as it should during the break-in.
Check accessories and other items
Another of the common uses of the multimeter in the vehicle is to verify that the different electrical elements of the same work correctly. With the multimeter we can verify if a certain component of the car has current or not, which will help us to diagnose its condition. Because a part that fails because it is damaged is not the same as one that fails because it does not get the energy it needs to fulfill its mission.
In this case, the measurement process requires placing the multimeter in the current measurement position and placing the rods between the input and output socket of the element to be verified, or in the two connectors or pins of the same, depending on its nature. In the event that we do not obtain a reading of the current flow, this is a sign that the component is not getting electrical power and, therefore, it is impossible for it to work. In case we get a proper current reading then we can rule out electrical failure as the cause of the problem.
Among the elements that we can verify with this system we have the connection cables of the vehicle, whose resistance must be 0.01 ohms. Otherwise, it will be necessary to check the voltage drop along the cable, as this may be a sign of faults or cable defect. The multimeter can also be used to verify the status of a fuse that, if it does not work correctly, will show a voltage of 0 volts. Something logical if we take into account that the role of the fuse is precisely to cut the voltage when it exceeds its capacity.
Although this use is not usually present in all multimeters, the truth is that some of them do have the possibility of measuring temperatures. To do this, these multimeters modify one of the rods with a specific probe, which is sometimes connected to a different port than the one normally used by conventional rods.
To proceed, you just need to place said probe, select the temperature measurement mode and bring it closer to the area of the vehicle that we want to measure. At the moment, we will have the corresponding temperature measurement on the screen. Something that can be useful to measure the temperature of the oil or the radiator, in order to check possible erroneous readings or verify the operation of the water and oil thermometer that many vehicles incorporate.