The multimeter is designed to test the parameters of electrical networks and electronic components. To an inexperienced person, the control of this device will seem difficult. But in fact, it is enough to understand the principle of taking readings and setting the settings. After that, it will seem that without it you can’t even change the outlet, and this is true.
What is this device, and what functions can it perform? At the first stage of acquaintance with the operation of the multimeter, it is necessary to understand its settings and capabilities. On almost all models, the designations are in Latin and are abbreviations or abbreviations for English terms.
Now, knowing the "language" of the device, you can begin to study its capabilities. The name multimeter (or multitester) means a wide range of measurements of various electrical quantities:
- DC and AC voltage and current.
- Resistance value.
- Capacity. This feature is found mostly only in professional devices.
For domestic needs, you can purchase a standard digital multimeter with an optimal set of functions. Since domestic manufacturers practically do not produce devices of this class, the choice stops at foreign digital multimeters.
The working panel of the device is divided into two conditional sectors - the LCD display and the settings block. The latter is most often a circular switch with markings applied around it. It, in turn, is divided by measured values with the maximum value of the measurement limits.
Measurements are performed using probes that are installed in special sockets on the device.
Before starting testing, the batteries and the performance of the device are checked. By turning the switch to any position other than "Off", the indicator should display zeros. Now you can start measuring the quantities of interest.
First, the upper limit level is set. For example, for a constant voltage, it can be from 200 mV to 1000 V. If at least the order of the value is known, the upper limit closest to it is set. Otherwise, it is recommended to set the maximum value and reduce it until, during the measurement process, numbers other than zero appear on the indicator. If you do not follow this technique, then there will be a possibility of failure of the device.
Voltage
Almost all household appliances and batteries operate on direct voltage. This is the most commonly measured value. The first experience of taking readings will begin with her.
We install the probes in accordance with the color markings. If this is not observed, find the designation “+” or “-” on the probe body. After that, the maximum value of the DC voltage force is set. In our case, this is 1000 V. Next, the probe contacts touch the corresponding poles of the element under test. In this case, you can not be afraid of erroneous polarity - the value on the screen will only change its sign.
By lowering the boundary limit by switching the handle, we stop when stable readings appear on the display.
AC voltage is measured in the same way. The exception is the lack of polarity.
Current
When measuring direct current, you should consider in advance how the multimeter will be connected to the circuit under test. This task is considered individually for each case. If there is no experience in drawing up such schemes, it is best to study the theory first. Otherwise, there is a high probability of damage to the multimeter.
Another important point is the location of the probes in the sockets. If the desired current parameter is guaranteed to be less than 200 mA, then their location remains standard. But with readings above 200 mA and up to 10A, one of the probes is installed in a special connector.
The simplest examples of measuring currents of various magnitudes are shown below.
Resistance
Measuring the resistance value can be useful not only for checking the parameters of the electrical network. Such a function will be useful when installing an electric underfloor heating or any other heating systems powered by electricity.
The principle of measurement is completely similar to the stages of finding the value of direct voltage. You need to move the toggle switch to the desired sector.
Professional electricians and electronics engineers, in addition to these basic types of readings, know many other parameters that can be directly or indirectly measured using a multimeter. But for domestic needs, the above information will be enough, and soon using a multimeter will be as familiar as.
Despite the versatility and versatility of modern measuring instruments, professional engineers choose a multimeter based primarily on those physical quantities that require the most accurate measurement possible.
A professional multimeter is a device that can fully satisfy the need for measurements in a narrow specialized field. Experts, reading the technical specifications, know exactly what to look for in order to choose the best tool for themselves, based on the price-quality ratio.
Therefore, this review of the functionality of various multimeters is intended for beginners, so that on the one hand they have a set of necessary functions, on the other hand they do not overpay for unnecessary features.
Measurement principles
There are general concepts regarding how to use a multimeter in the process of making measurements, which are:
Letter designation of functionality
Without reference to a specific physical quantity, it is impossible to answer the question of how to use a multimeter. Long gone are the days when multimeters measured only current, voltage, and resistance, so one instruction was suitable for all devices.
Designation on the panel for measuring different quantities Modern multimeters have many different functions, which are grouped in one device depending on the specialization, and are described in the corresponding instructions from the manufacturer. To facilitate the search for the desired device, in the catalogs, to reduce the designation of the functionality of the multimeter, alphabetic indices are used, which are capital letters of the English names of the measured physical parameters.
The most common:
- T - (temperature), measures the temperature;
- F - (frequency) frequency meter (for frequency measurements);
- C - (condenser capacity) capacitor capacity;
- L - the designation of inductance, adopted in honor of the physicist Emil Lenz (Lenz);
- R - (resistance), resistance.
Thus, for example, with a CRL multimeter, you can measure capacitance, resistance, inductance. On the case of a typical budget multimeter (for "dummies"), there are such designations:
Some measurement designations on the multimeter case Multimeter in the household
Speaking about how to use a multimeter in everyday life, you need to imagine everyday situations when this may be needed. Very often in the household it is necessary to check the integrity of the electrical circuit (ring the wiring), or check it for an unacceptable short circuit.
For these purposes, a budget multimeter is suitable, as in the picture. The red probe is inserted into the V, R, mA connector, the black one into COM, the device is switched to the “ringing” mode, indicated by a diode or an audio speaker. After that, two probes are closed, checking the operability - a signal should sound.
Working with a multimeter in open circuit and when the circuit is closed Let's say you need to ring the Internet cable. First you need to put two connectors side by side. By touching the probes to the terminals connected to the wires of the same color, a signal is achieved. If there is no signal, then there is a break somewhere (no contact).
"Continuity" of the Internet cable When checking the cable, the digital display shows resistance, that is, if the switch of the multimeter does not have a diode or speaker, then you can check the cable with an ohmmeter, even using an arrow multimeter. The dialing mode is the only measuring function that can be carried out using a pointer device, without understanding the scale graduation and the measured values.
To check the quality of electricity in the outlet, you need to switch to V ~ 750 mode, insert the probes and observe the changing voltage for some time.
Also in this measurement mode, you can determine the phase. To do this, one probe is grounded (connected to the shield body or to ground), and the other is checked for wires or contact terminals. Appearing 220V (or so) on the display will indicate that the wire being tested is a phase.
Determining the phase with a multimeter Often, the rated current is indicated in the passport of household appliances. To measure the current flowing in the circuit, the multimeter must be included in its break. To do this, set the multimeter switch to the maximum value of the A~ range (alternating current, 20 A).
Probes must be connected to the appropriate connectors
For safe connection of bare conductors, a 12V lamp powered by a transformer is used.
Connecting a 12 V light bulb through a transformer Under mains voltage, in a similar way, it is impossible to measure the current because of the danger of injury. But, it is possible to build a test stand by safely inserting the probes into one outlet and connecting the load to another.
test bench It is necessary to check resistors or other electronic electronic devices in the ohmmeter mode, switching the corresponding ranges, in the same way as the continuity was made.
When measuring kiloohms and megaohms, it is necessary to avoid touching the pins of the parts with your fingers - the human body has resistance, which will affect the accuracy of measurements.
You can't measure like that! 
So you can measure! Element properties
To use a multimeter, it is also necessary to understand the properties of the elements being tested. For example, contrary to popular belief, you cannot check the battery charge with a multimeter using a single voltage measurement - a battery or car battery will show a value close to the nominal value, with the exception of fully planted batteries.
Circuit for measuring voltage, current and resistance These current sources tend to restore voltage due to the chemical processes occurring inside, but when doing work, the voltage drops on a dead battery. But, you can make a measurement of the current strength (through connection of a multimeter, or using shunts) flowing in the load connected to the battery terminals, selecting the appropriate load resistance, and then go and switch to voltage mode, in this way calculating the output power of the power source.
By observing the dynamics of the voltage drop, you can judge how the battery is discharged. To explain how to test a capacitor with a multimeter, you need to understand the property of active capacitance, which decreases as capacitance increases with alternating current.
Soviet pointer multimeters of the Ts series were connected to an outlet to obtain a reference frequency and, using an additional terminal, measured the capacitance of the capacitors. Modern multimeters have their own built-in generator for such measurements, which are made by connecting the probes to the capacitor electrodes.
Capacitor capacitance measurement The DMMs have internal electronic protection to prevent misuse, and a built-in thermal fuse. Automatic power off helps conserve battery power.
When choosing a multimeter, be sure to check how it works if the battery is partially planted - cheap Chinese models in this case give a very large measurement error.
Be sure to observe safety and monitor the condition of the measuring probes and wire insulation - very often they come off the probes, and during measurements can cause electrical injury.
A multimeter is one of the inexpensive measuring instruments that is used by both professionals and amateurs repairing home wiring and electrical appliances. Without it, any electrician feels like without hands. Previously, three different instruments were required to measure voltage, current, resistance. Now all this can be measured using one universal device. Using a digital multimeter is very easy.
There are two main rules to remember:
- ⚡ where to connect the measuring probes
- ⚡ in what position to set the switch for measuring different values
Multimeter appearance and connectors
On the front of the tester, all the inscriptions are made in English, and even with the use of an abbreviation.
What do these inscriptions mean:
- OFF - the device is turned off (so that the batteries of the device do not run out, set the switch to this position after measurements)
- ACV - variable U measurement
- DCV - constant U measurement
- DCA - DC current measurement
- Ω - resistance measurement
- hFE - measurement of transistor characteristics
- diode icon - continuity or diode test
Switching modes occurs using the central rotary switch. At the very beginning of using the DMM, it is recommended that you immediately mark the pointer mark on the switch with contrasting paint. For example like this: 
Most of the failures of the device are just due to the wrong choice of the switch position.
Power is supplied from a battery type krone. By the way, by the connector for connecting the crown, you can indirectly judge whether the tester was assembled in the factory or somewhere in Chinese "cooperatives". With high-quality assembly, the connection occurs through special connectors designed for the crown. In lower quality versions, conventional springs are used.
The multimeter has several connectors for connecting probes and only two probes. Therefore, it is important to correctly connect the probes to measure certain quantities, otherwise you can easily burn the device.
The probes are usually of different colors - red and black. The black probe is connected to the connector labeled COM (translated as “common”). Red probe into the other two connectors. The 10ADC connector is used when it is necessary to measure the current strength from 200mA to 10A. The VΩmA connector is used for all other measurements - voltage, current up to 200mA, resistance, continuity. 
The main criticism is caused precisely by the factory probes that come with the device. Almost every second multimeter owner recommends replacing them with better ones. True, at the same time, their cost can be comparable to the cost of the tester itself. In the extreme case, they can be improved by reinforcing the bends in the wires and insulating the probe tips. 
If you want high-quality silicone probes with a bunch of tips, then you can order them with free shipping on AliExpress. 
Previously, pointer testers were also widely used. Some electricians even prefer them, considering them more reliable. However, it is less convenient for ordinary consumers to use them because of the large error in the measurement scale. In addition, when working with a dial multimeter, it is imperative to guess the polarity of the contacts. For digital, if the poles are not connected correctly, the readings will simply be displayed with a minus sign. This is the normal mode of operation, which will not damage the multimeter. 
Basic operation of the multimeter
Voltage measurement
How to use a digital multimeter to measure voltage? To do this, put the switch on the multimeter in the appropriate position. If this is the voltage in the socket at home (alternating voltage), then flip the switch to the ACV position. Insert the probes into the COM and VΩmA connectors. 
First of all, check the correct connection of the connectors. If one of them is mistakenly set to contact 10ADC, a short circuit will occur when measuring the voltage.
Start the measurement from the maximum value on the device - 750V. The polarity of the probes does not play any role at all. It is not necessary to touch zero with a black probe, and phase with red. If a much smaller value appears on the screen, and the number “0” is in front of it, this means that for a more accurate measurement, you can switch to another mode, with a smaller voltage level scale that your multimeter allows you to measure.
When measuring DC voltage (for example, electrical wiring in a car), switch to DCV mode. 
And also start measurements from the largest scale, gradually lowering the measurement steps. To measure voltage, you need to connect the probes in parallel with the circuit being measured, while holding on to only the insulated part of the probe with your fingers so as not to get energized yourself. If the display shows the voltage value with a minus sign, this means that you have reversed the polarity.
ATTENTION: when measuring voltage, be sure to check that the multimeter scale is set correctly. If you start measuring voltage with the DCA switch on, that is, to measure current, then you can easily create a short circuit directly in your hands!
Some experienced electricians advise holding both probes in one hand when measuring the voltage at the outlet. With poor insulation of the probes and their breakdown, this will allow you to protect yourself to some extent from electric shock.
The multimeter is battery operated (a 9 volt crown is used). If the battery starts to run low, the multimeter begins to shamelessly lie. In the outlet, instead of 220V, all 300 or 100 Volts may seem. Therefore, if the readings of the device start to surprise you, first of all check the power. An indirect sign of battery discharge may be chaotic changes in the readings on the display, even when the probes are not connected to the object being measured.
Current measurement
The device can only measure direct current. The switch must be in the -DCA position. 
Be careful! When measuring current, if you do not know approximately what the current strength will be, it is better to start measuring by inserting the probe into the 10ADC connector, otherwise measuring the current more than 200mA at the VΩmA connector, you can easily burn the internal fuse.
Here, the probes, unlike voltage measurements, must be connected in series with the measured object. That is, you will have to break the circuit and then connect the probes to the resulting gap. You can do this in any convenient place (at the beginning, middle, end of the chain). 
In order not to constantly hold the probes with your hands, you can use alligator clips to attach. 
Be aware that if you mistakenly put the switch in ACV mode (voltage measurement) when measuring current, then with a high probability nothing bad will happen to the device. But if the opposite is true, then the multimeter will fail.
Resistance measurement
To measure the resistance, put the switch in position - Ω. 
Choose the desired resistance value, or again start with the largest. If you are measuring resistance on a working device or wire, it is recommended to turn off the power from it (even from a battery). Thus, the measurement data will be more accurate. If, during the measurement, the display shows the value “1, OL”, this means that the device is signaling an overload and the switch must be set to a larger measurement range. If “0” is displayed, then vice versa, reduce the measurement scale.
Most often, a multimeter in resistance mode is used during repair work, to check the performance of household appliances, the health of the windings, and the absence of a short circuit in the circuit.
When measuring resistance, do not touch the bare parts of the probes with your fingers - this will affect the accuracy of the measurements.
dialing
Another mode of operation of the tester that is often used is dialing.
What is it for? For example, in order to find an open in the circuit, or vice versa - to make sure that the circuit is not damaged (checking the integrity of the fuse). Here the level of resistance is no longer important, it is important to understand what is happening with the chain itself - is it whole or not.
It should be noted that there is no sound signal on the DT830B.
For other brands, as a rule, a signal is heard when the circuit resistance is not more than 80 ohms. The dialing mode itself occurs at the position of the pointer - checking the diodes. 
With a dial, it is also useful to check the integrity of the probes themselves by closing them with each other. Since with frequent use they may be damaged, especially at the point where the wire enters the probe tube. Before each measurement, make sure that there is no voltage in the area where you will connect the probes for continuity, otherwise you can burn the device or create a short circuit.
Safety precautions when working with a multimeter
- ⚡ do not take measurements in a damp room
- ⚡ do not switch the measurement limits at the time of the measurements themselves
- ⚡ do not measure voltage and current if their values \u200b\u200bare greater than those for which the multimeter is designed
- ⚡ use probes with good insulation
I hope this material helped you get acquainted with the basic parameters of the multimeter. And you can safely and productively use it for repair work.
Not so long ago, we crossed a new frontier and became an information society. Partial automation of workplaces has taken place in almost all areas of activity. Where the computer could not completely replace the person, there were jobs "man at the computer."
As a result, the ability to use a computer has become an urgent need for many people who until that time had not encountered this "wonder machine".
What does computer consist of?
In order to know how to use a computer correctly, you need to consider its main components.
So, a computer consists of a system unit ("computer's brain"), a monitor ("computer's eyes" - an information output device), a keyboard and a mouse ("computer's hands" - an information input device). Without these main components, this computer will not work. Of course, without a mouse, the computer will turn on, but without it, you yourself will not be able to work at first, since for this you need to know the keyboard shortcut functions.
How to start using a computer?
After you have figured out the components of the computer, you can try turning it on and off. The power button in most cases is located on the front side of the system unit, has a fairly large size, and when pressed, it lights up in green or red.
In order to turn off the computer you need to click on the "Start" button on the taskbar. The taskbar is located at the very bottom ("at the bottom") of the screen. After pressing this button, the menu of the Start button will open, i.e. available computer actions. The last line of the menu - "Turn off the computer" with a red icon in the form of a button - click on this line. Most likely, the computer will "ask" you again - what action should be performed, because using this menu bar you can also restart the computer. Click in the window that appears again the red icon in the form of a button.
Computer Basics
After we have figured out how to properly turn on and off the computer (these actions extend the life of this device), you can begin to use it directly.
In fact, there are a lot of actions with a computer that can be operated on. We will consider the basic, most simple actions, without which you will not be able to work at a computer:
Good luck in learning new things!
Hello, dear visitors of the site.
Well, I finally got to writing an article on how to use a multimeter. A lot of letters come from you on this issue. Interested mainly in how to carry out this or that measurement. But first things first.
In general, I think that a multimeter is one of the most necessary devices for diagnostics and repairs, both in production and at home. Therefore, it is always present in mine. With it, you can spend a large number of:
- AC voltage and current
- constant voltage and current
- electrical resistance
- containers
- frequencies
- temperature
- parameters of transistors and diodes
By the way, even recently, instead of multimeters, we used analog (pointer) devices of the Ts4342 type. Or maybe someone still uses it.
In the common people they are simply called "tseshka".
Therefore, until today, I call the multimeter "tseshka". It just so happened - I'm used to it.
I like multimeters for their simplicity and versatility. However, here it is worth noting the direct proportional dependence of the functionality of the multimeter on the price. The more expensive the multimeter, the wider its capabilities. Do not forget about quality.
Personally, I use the following multimeters ("testers"):
- Fluke 123
- М4583/2Ц
- М890D
Fluke 123 is a professional multimeter, and if you believe the passport, then an oscilloscope. And he has a price to match. The photo below shows a graph of the supply voltage of 220 (V) at one of the substations, made by the Fluke 123 device. And as you can see from the graph, the voltage is very unstable at some hours. As a result, it turned out that at night someone unauthorizedly connected to assembly 380/220 (B) and carried out welding work. The culprit was found and punished. Thanks to the device for accurate and reliable information.
The rest of the multimeters are simpler and cheaper.
Therefore, in this article I will tell you how to use a simple M890D digital multimeter.
In terms of dimensions, the M890D multimeter is quite small and compact, and is portable. It includes measuring probes (red and black).
I want to immediately warn you so that you are not surprised when you see blue electrical tape on the probes. This is the "disease" of all low-quality probes.
The fact is that with the active use of the multimeter, the wires often break. This happens due to the fact that the wire running in the probe tube rests only on the soldering of the metal lead and rotates freely. The way out of this situation, in addition to fixing the wire to the tube with electrical tape, is to purchase high-quality probes. For example, these:
The power source for the multimeter is a 9 (V) Krona battery, which is located inside the case. To replace the battery, unscrew the screw on the back cover of the multimeter.
A protective fuse is also installed there.
Introduction
First, let's get acquainted with the external image of the multimeter. For almost all multimeters, the measured parameters are divided into sectors circled by the corresponding lines. In the center there is a switch with which the required parameter and measurement limit are selected.
The multimeter is turned off by pressing the "auto off power" button.
For some models, the multimeter is turned off by moving the switch to the "off" position.
Electrical safety when working with a multimeter ("tester")
When working with a multimeter, the following rules must be strictly observed.
- do not use the multimeter in a humid environment
- it is forbidden to change the position of the switch and the measurement limit during the measurement
- it is forbidden to measure the parameter above the upper limit of the measurement of the device
- it is forbidden to use a multimeter with faulty measuring probes
How to use a multimeter when measuring DC voltage
When measuring the DC voltage with a multimeter, insert the red measuring probe into the “V / Ω” jack, and the black probe into the “com” jack.
It is customary to take the “+” potential for the red probe, and the black probe for the “-” potential.
We set the multimeter switch to the range (-V). It is highlighted in green. There are 5 measurement limits in this range: 200 (mV), 2 (V), 20 (V), 200 (V) and 1000 (V).
For example, let's measure the DC voltage on a battery (battery) of the "Krona" type with a voltage of 9 (V).
Therefore, you can immediately set the switch to the limit "20", which will correspond to the measurement limit of the multimeter from 0 to 20 (V). We connect the measuring probes to the measured object on the "+" and "-" battery contacts.
On the display we look at the value of the constant voltage, which is 9.99 (V). Almost 10 (B).
You see, there is nothing difficult.
If on the display screen of the multimeter (tester) there is a minus sign in front of the value, then this means that the wrong polarity is selected - you need to swap the measuring probes.
And what to do when the value of the measured direct voltage is unknown?
When the value of the measured DC voltage is unknown, then the measurement must be started from the maximum limit of "1000", which will correspond to the measurement limit of the multimeter from 0 to 1000 (V). I talked about this a little higher, otherwise you can burn the multimeter.
Suppose that we do not know the voltage of our "Krona". Then we set the multimeter switch to the limit "1000" and carry out the measurement. In this case, we will see the value 008 (B) on the tester screen. Before the obtained value, there are immediately two zeros - this indicates that the measurement limit can be reduced.
Next, set the limit to “200” with the switch, which will correspond to the measurement limit of the multimeter from 0 to 200 (V), and again we measure. Now on the screen of the multimeter we see a reading other than zero, and it is 09.9 (V). But before the value there is again a zero, which indicates that the measurement limit can be reduced again.
Once again, we reduce the measurement limit of the multimeter and set it to the limit of "20". And only after that, the real value of the measured constant voltage of the Krona was displayed on the display screen and it amounted to 10 (V).
I think this is sorted out.
There are times when the value “1” appears on the display of the multimeter (tester).
This means that the selected measurement limit is chosen lower than the value of the measured quantity.
How to use a multimeter when measuring AC voltage
When measuring the AC voltage with a multimeter, insert the red measuring probe into the “V / Ω” jack, and the black probe into the “com” jack. In general, as when measuring direct voltage.
We set the multimeter switch to the range (~ V). It is highlighted in white. There are 4 measurement limits in this range: 2 (V), 20 (V), 200 (V) and 700 (V).
) is about 220 (V) depending on the load on your supply transformer. At least that's how it should be. At the same time, we will check how much the voltage in our house differs from the “ideal” one.
We set the multimeter switch to the limit "700", which will correspond to the measurement limit of the multimeter from 0 to 700 (V), and we measure the AC voltage in the home network. The probes can be inserted in any order and interchanged during measurement.
I told you about electrical safety when taking measurements with a multimeter at the beginning of the article.
The measured AC voltage of the home network, which we see on the screen of the multimeter, is 231 (V).
By the way, in some of my articles I have already given examples of using a multimeter when measuring various circuit parameters. For example, in articles about
