Measure the resistance. How to check resistance with a tester? How to use a multimeter when measuring DC voltage

Resistance is a physical quantity that characterizes the properties of a body (object) to prevent the passage of electric current. To some extent, resistance is similar to the frictional force that occurs when a body moves along a certain surface. Resistance is measured in ohms (Ohms): 1 Ohm = 1 V (volts, voltage) / 1 A (amps, current). Resistance is measured using an ohmmeter or a digital or analog multimeter.

Steps

Measuring Resistance with a Digital Multimeter

Touch one terminal of the element with one probe, and touch the opposite terminal of the element with the second probe. Wait until the numbers on the indicator stop changing and write down the displayed number, which is the resistance value of the resistor.
- For example, if the meter displays "0.6" and its upper right corner displays "MΩ", then the resistor value is 0.6 MΩ.
Turn off the multimeter. When you have finished measuring the resistance of the resistors, turn off the multimeter and disconnect the probes.

Measuring resistance using an analog multimeter
1. Select the element whose resistance you want to measure. To get an accurate result, measure the resistance of each element of the circuit (circuit). To do this, either remove the element from the circuit or measure the resistance before connecting the element to the circuit. Measuring the resistance of an element connected to a circuit may lead to inaccurate results due to the influence of other elements.
  
  Connect the multimeter probes to the appropriate connectors. Most multimeters have two probes - black and red, as well as several connectors that are designed to measure various quantities - resistance, voltage or current. As a rule, connectors designed to measure resistance are designated by the letters “COM” (English “common” - standard) and the Greek letter Ω (omega), which is a symbol of the unit of measurement ohm.
  - Connect the black lead to the jack labeled "COM" and the red lead to the jack labeled "Ohm".
2. Turn on the multimeter and set the measurement range. The resistance of the element can range from several ohms (1 ohm) to several megaohms (1,000,000 ohms). For accurate results, set the resistance value range that matches the selected element. Some digital multimeters set this range automatically, while others do it manually. If you know what range the resistance of the selected element lies in, set the appropriate range; otherwise, determine the range by trial and error.
  - If you don't know the range, set the middle range first; Typically, this range is 0–20 kOhm.
  - Touch one terminal of the element (resistor) with one probe, and touch the opposite terminal of the element with the second probe.
  - The indicator arrow will begin to move along the scale and stop at a certain number, indicating the resistance value of the element.
  - If the needle moves toward the maximum range limit (left side), narrow the set range, reset the multimeter to zero (set the needle to zero), and repeat the measurement.
  - If the needle moves toward the minimum range limit (right side), expand the specified range, reset the multimeter to zero, and measure again.
  - Analog multimeters should be reset after each range change. To do this, touch one probe to another to cause a short circuit. If the needle is not at zero, adjust its position using a special regulator (“Ohm regulator” or “Zero control”).
3. Touch the leads of the multimeter to the terminals of the resistor whose resistance you want to measure. Touch one terminal of the element with one probe, and touch the opposite terminal of the element with the second probe. The arrow will begin to move from right to left - the minimum resistance value (right) is zero, and the maximum value (left) is 2000 Ohms (2 kOhms). An analog multimeter has multiple scales, so look for the resistance value on the scale labeled "Ω" (Ohm).
  - As the values increase, the numbers on the scale will cluster closer together. Therefore, setting the correct range is critical to obtaining accurate readings.
4. Definition of resistance. By touching the resistor terminals with the probes, the needle will stop somewhere in the middle of the scale. Make sure you read the value from the scale marked "Ω" (ohms); Write down the number that the arrow points to - it is the resistance value of the resistor.
  - For example, if the range you set is 0-10 ohms, and the arrow stops at the number 9, then the resistance of the element is 9 ohms.
5. Set the maximum voltage range. When you finish using the multimeter, turn it off properly. To do this, set the voltage range to the maximum so you don't damage the device the next time you (or someone else) forgets to set the range in the first place. Turn off the multimeter and disconnect the probes.
Getting accurate measurement results
1. Measure the resistance of the de-energized element. The current passing through the circuit will negatively affect the accuracy of the multimeter readings, as it affects the resistance value of the resistors. In addition, additional voltage may damage the multimeter (so it is not recommended to measure the resistance of a battery or accumulator).
  - When measuring the resistance of a capacitor in a circuit, you must first discharge it. A discharged capacitor will be charged by the multimeter, which will lead to short-term jumps in the readings of the device.

If you are wondering " How to use a multimeter?", then you at least already know what electric current and voltage are. If not, then I suggest you read the first chapters of my electronics textbook.

So what is a multimeter?

Multimeter - This is a universal combined measuring instrument that combines the functions of several measuring instruments, that is, it can measure a whole range of electrical quantities.

The smallest set of functions of a multimeter is the measurement of voltage, current and resistance. However, modern manufacturers do not stop there, but add to the set of functions such as measuring the capacitance of capacitors, current frequency, diode continuity (measuring the voltage drop at the p-n junction), an audio probe, temperature measurement, measuring some transistor parameters, a built-in low-frequency generator and much more. With such a set of functions of a modern multimeter, the question really arises: how to use it?

In addition, multimeters are digital and analog . Let’s not go deeper into the weeds, I’ll just say that they differ externally in the instruments used to display the measured values. In an analog multimeter it is a pointer indicator, in a digital one it is a seven-segment indicator. However, we are accustomed to understanding the word multimeter as a digital multimeter. Therefore, in this article I will tell you how to use a digital multimeter.

For example, let's take the widely used multimeters of the series M-830 or DT-830. There are several modifications in this series, their markings differ in the last digit, as well as the set of functions included in this device.

I plan to review multimeters from this line in one of the next issues of the magazine, so do not forget to subscribe to new issues of the magazine at the end of the article. I will describe how to work with a multimeter using an example. device M-831.

The main functions of the M-831 digital multimeter and the purpose of the device controls

Let's take a closer look at the external panel of the multimeter. Here we see in the upper part a seven-segment liquid crystal indicator, on which the values we measure will be displayed.

Let's take a closer look at all the symbols that are printed in a circle, thereby analyzing the operating modes of the multimeter.

1 - turn off the multimeter.

2 - mode for measuring alternating voltage values, has two measurement ranges of 200 and 600 volts.

ACV - AC Voltage- (eng. Alternating Current Voltage) - alternating voltage

3 - mode for measuring direct current values in the following ranges: 200 µA, 2000 µA, 20 mA, 200 mA.

Other multimeter models may use the designation DCA- (eng. Direct Current Amperage) - direct current.

4 - mode for measuring large values of direct current up to 10 amperes.

5 - audio testing of wires, the sound signal is turned on when the resistance of the section being tested is less than 50 Ohms.

6 - checking the health of the diodes, shows the voltage drop at the p-n junction of the diode.

7 - mode for measuring resistance values, has five ranges: 200 Ohm, 2000 Ohm, 20 kOhm, 200 kOhm, 2000 kOhm.

8 - mode for measuring DC voltage values, has five ranges: 200 mV, 2000 mV, 20 V, 200 V and 600 V.

Other multimeter models may use the designation DCV - DC Voltage- (eng. Direct Current Voltage) - constant voltage.

In the lower right corner of the front panel of the multimeter there are three sockets for connecting the included cords with probes.

Everything is simple here:

Bottom socket for the common (negative) wire in all modes and on all ranges;

Middle socket for positive wire in all modes and on all ranges except for current measurement mode up to 10 A;

The upper socket for the positive wire in current measurement mode up to 10 A.

Be careful, when measuring current more than 200 mA, connect the positive wire only to the upper socket!

The multimeter is powered by a 9-volt Krona battery or according to the standard size - 6F22.

Inside, under the back cover of the multimeter there is a fuse, usually 250 mA, which protects the device in current measurement mode up to 200 mA.

Measuring electrical quantities with a multimeter

So, it's time to learn how to use a multimeter. We will learn to measure electrical quantities using the same M-831 multimeter as an example. Let me remind you once again that with this multimeter you can measure direct and alternating voltage up to 600 volts, only direct current values up to 10 amperes and electrical (active) resistance values up to 2 megaohms.

Let me remind you that to measure the voltage on an element (section) of an electrical circuit, the device is connected in parallel to this element (or section of the circuit).

To measure current in a circuit, the device is connected to the open circuit of the circuit being measured (that is, in series with the circuit elements).

How to use a multimeter when measuring DC voltage.

Now let me tell you in detail, step by step, how to measure DC voltage with our multimeter.

The first thing you need to do is select the type of voltage being measured and the measurement limit. To measure DC voltage, the multimeter has a whole range of DC voltage values, which are set using the limit switch.

To set the measurement limit, we first determine approximately what voltage value we want to measure. Here you need to act according to the situation, if you measure the voltage of the batteries (batteries, accumulators), then look for the inscriptions on the elements, if you measure the voltage in various electrical circuits, then I think since you “got into it”, then you already know how use a multimeter!

Let's say we need to measure the DC voltage on a battery from some electronic device (I'll take a video camera battery).

1. We carefully study the inscriptions on the battery, we see that the battery voltage is 7.4 volts.

2. We set the measurement limit to be greater than this voltage, but preferably close to this value, then the measurements will be more accurate.

For our example, the measurement limit is 20 volts.

Nevertheless, when measuring voltage, for example in circuits, I advise you to set the limit higher than the supply voltage of the circuit, so as not to cause the device to fail.

3. Connect the multimeter to the battery terminals (or parallel to the area where you measure the voltage).

A black probe, one end to the COM socket of the multimeter, the other to the minus of the measured voltage source;

Red probe to the VΩmA socket and to the plus of the measured voltage source.

4. Read the DC voltage value from the LCD indicator.

Note: if you do not know the approximate value of the measured voltage value, then the measurement must begin by setting the highest limit, that is, for M-831 - 600 volts, and successively approach the limit closest to the measured voltage value.

How to use a multimeter when measuring AC voltage.

Measuring alternating voltage is carried out on the same principle as measuring direct voltage.

Switch the device to AC voltage measurement mode by selecting the appropriate AC voltage measurement limit.

How to use a multimeter when measuring DC current.

Let me remind you that the 830 series instruments measure only DC current values, so if you need to measure current in an AC circuit, then look for another instrument.

A multimeter for measuring current is connected to the open circuit of the circuit being measured.

Again, it is necessary to determine the maximum possible current value in the circuit being measured.

If the current values are less than 200 mA, then select the appropriate measurement limit, connect the red probe to the socket VΩmA and connect the multimeter to the open circuit.

To measure current in the range 200 mA-10 A, connect the red probe to the socket 10A .

It is advisable to connect the multimeter in current measurement mode to the circuit when the voltage in the circuit is removed, and at the limit of 10A this is a mandatory operation, since at high currents it is not at all safe.

And the last nuance: in the characteristics of devices from some manufacturers it is not recommended to turn on the multimeter to measure current at a limit of 10 A for more than 15 seconds.

How to use a multimeter when measuring resistance.

To measure resistance using a multimeter, the latter must be switched to one of five resistance measurement limits.

Moreover, the rules for choosing the measurement limit are as follows:

1. If you know in advance the value of the measured resistance (for example, in the case of checking a resistor for “good” or “faulty”), then the measurement limit is selected greater than the value of the measured resistance, but as close to it as possible. Only in this case will you minimize the error in resistance measurement.

2. If you do not know the value of the measured resistance in advance, then you need to set the maximum measurement limit (for M-831 this is 2000 kOhm) and, by changing the limits, consistently approach the measured resistance value.

Note: if “1” is displayed on the multimeter screen, then the value of the measured resistance is greater than the set measurement limit, in this case it is necessary to switch the limit towards its increase.

To measure resistance, simply connect the probes of the device to the element whose resistance you want to measure and take readings from the device indicator.

Watch this video and learn not only how to measure current, voltage and resistance, but also how to test wires and check the health of diodes using a multimeter!

The list of possible applications of a multimeter in the practice of a radio amateur is huge. We will be interested in one question here: is it possible and how to check the resistance with a multimeter? Of course, you can check it, because an ohmmeter is inserted into the design of this device. It is with its help that you can measure the resistance of cable lines, all radio components, transformers, inductors, fuses and capacitors.

If we look at the schematic diagram of an ohmmeter, then this is a circle, inside of which there is this letter of the Latin alphabet - “Ω” (omega), as well as two terminals, which represent the two probes of the device. By the way, the letter omega means resistance in physics.

Since there is quite a wide variety of multimeter models on the market, the location of the designations on the housing may be different. But since our task is to measure resistance with a tester, we will be interested in the panel where this very letter “Ω” is located. There is also a manual switch and several measurement limits. On some models there may be five, on others seven. The designation is made by numbers and letters.

For example, the limit may be “200”, which means the resistance is measured up to 200 Ohms. There may be either such a designation as “2000”, or such as “2k”. This is the same thing - the limit defines up to 2000 Ohms or 2 kOhms, which is the same indicator. The same is true with the following designations: 2M or 2000k - up to 2,000,000 Ohms. So that you understand what we are talking about, below is a photo of the multimeter panel, where everything is clearly visible:

Let's give an example. You have a coil or any radio component on your hands, the approximate resistance of which is 1000 Ohms or 1 kOhm, then you need to set the resistance limit higher than the approximate one. If you look at the photo, you will understand that the measured resistance will be a limit of 2 kOhms. On some models there is no such indicator, so it is set to 20 kiloohms.

Now the measurement process itself. But first we need to remind you (who doesn’t know) that the red probe is inserted into the hole (socket) “V/Ω”, and the black one into “com”. In this case, a check is made, that is, both probes are connected. Zeros should appear on the display. Of course, the switch itself must first be set to the range designated omega.

Measuring indicators of the multimeter

So, the approximate resistance is 1 kOhm. An inspection is underway. Now pay attention to the display, if one appears on it, then the part being tested has a higher resistance. This means that you need to reinstall the multimeter to a higher position. In our case, according to the photo it is 20 kOhm. We install it and take additional measurements.

Attention! Do not touch bare areas of probes and leads of radio components. The thing is that the human body also has its own resistance, which means that the multimeter will show on the display the total indicator: the resistance of the body and the radio components. If there is a need to hold the probe or part, then this can be done with only one hand.

Features of measuring with a multimeter

It often becomes necessary to measure the resistance of a part that is soldered into the plateau. If you check the assembly, the indicator will be incorrect. Why? Because the element being tested will be connected by a circuit to other radio components, and, therefore, the multimeter will show the general indicator. Therefore, before testing, it is necessary to unsolder one pin of the element from the board, that is, disconnect it from the circuit.
When testing multi-pin elements, they must be completely dismantled. And after that, check their resistance to ensure a correct determination of the serviceability of the device.
The serviceability and integrity of the probes also affects the accuracy of the multimeter reading. It has already been discussed above how to check the device for its serviceability. But let’s add that if the probes are applied to each other or moved over each other, and if in this case the display readings jump (first one thing, then the other), then this means that there is a defect in the probes. This is a guarantee of an incorrect measurement. Therefore, it is worth replacing the probes with new ones.
The battery, built into the device and serving as a power source, plays an important role in the quality of the testing. Practice shows that as soon as the battery begins to discharge, the tester immediately begins to lie. Therefore, you should pay attention to the icon that indicates the battery and shows its charging. If it is reduced, then the battery must be replaced with a new one or the device must be recharged.

Let's return to the position of how to measure resistance. What I would like to add. All radio components have a resistance that is known, and it is marked or indicated in tables. This is no secret for radio amateurs. All elements have certain limits and tolerances. For example, resistors have a tolerance of plus or minus 10%. For example, when testing a resistor with a nominal resistance of 1 Megohm, you can get different results: from 990 kOhm to 1.1 Megohm. And this will be considered the correct indicator.

There are often questions regarding the accuracy of the test performed. Again, let's give an example based on a 1000 Ohm resistor. If you check it at the limit of 2000, then the readings will be “1” on the display. If you turn the switch to the limit up to 20k, then the readings may be, for example, 1.12 or something else, that is, more accurate. Therefore, when checking a radio component for resistance, it is necessary to carry out testing at different limits and select the most accurate indicator.

Please note that measuring current and voltage with a multimeter should start with high limits. With resistance it’s the other way around; you have to start from low positions. Why is this so? Because at low limits, if you measure an element with high resistance, the display will always show one. This means that by moving up the line of limits, you can reach the required indicator, which will show a reliable result.

Insulation resistance test

How to measure the insulation resistance of cable lines? The question is actually very serious. And let's start answering it with warnings. The insulation resistance of cables and wires can only be measured in the warm season or in heated rooms. Because ice can form inside the cable braid - frozen droplets of water. And everyone knows that ice is a dielectric, a material that does not conduct. This means that these ice inclusions will not be detected by resistance meters. After thawing, moisture will appear inside the wiring, which negatively affects the cable as a whole.

So, let's test. An insulation resistance meter must be installed by installing the two ends of the measuring instrument (megaohmmeter) on the end of the phase wire located in the distribution board, and on the end of the neutral wire located in the same place. In this case, their ends must be disconnected from the terminals. The measured resistance must be within certain limits, which are determined by the PUE. By the way, these rules contain tables with indicators of limits. Based on them, you will have to compare the obtained indicators, which will depend on the brand of cable and its cross-section.

Testing insulation resistance is a basic process that electricians typically use when checking the integrity of electrical wiring inside buildings (residential and non-residential).

Conclusion on the topic

Let's summarize the question of how to check resistance with a tester (multimeter)? In fact, this process is simple. The main thing is to correctly understand how to measure a given value, how to correctly set the device, what limits should be used. Since the device itself is manual, you will need to remember all the manipulations with switches and probes. If you understand and remember this, then you will not have problems with testing.

Hi all! Today we will talk again about such a device as a multimeter. This device, also called a tester, is designed to measure the basic characteristics of an electrical circuit, electrical appliances, in cars - in general, wherever there is electricity. We have already talked a little about multimeters, today we will touch in more detail on what and how they can measure. Once upon a time, the multimeter was the domain of only electricians. However, now many people use it.

There are many different models of multimeters. There is a class of instruments for measuring only certain characteristics. Multimeters are conventionally reduced to two types:

analog multimeters - data is displayed by an arrow. These are multimeters that are still used by people of the old school; they often cannot or do not want to work with modern instruments;
digital multimeters – data is displayed in numbers. This type of tester has replaced the pointer tester; for example, I prefer to use such a device.

Since digital devices are now the most common, we will consider the description of this device using its example. Below are the main symbols that are found on almost any multimeter model.

If you examine the front panel of the multimeter, you can see eight blocks with different symbols:

What does the multimeter show when selecting different operating modes?

They are located around a round switch, with which you can set the desired mode. On the switch, the contact point is indicated by a dot or a raised triangle. Designations are divided into sectors. Almost all modern multimeters have a similar layout and a round switch.

sector OFF. If you set the switch to this position, the device is turned off. There are also models that automatically turn off after a while. This is very convenient, because for example, I forget to turn it off while working, and it’s not convenient when you measure, then solder, turn it off all the time. The battery lasts a long time.

2 and 8– two sectors with the designation V, this symbol indicates voltage in volts. If just a symbol V– then the DC voltage is measured if V~, AC voltage is measured. The numbers next to them show the range of the measured voltage. Moreover, constant is measured from 200m (millivolts) to 1000 volts, and variable is measured from 100 to 750 volts.

3 and 4– two sectors for measuring direct current. Only one range is highlighted in red for measuring current up to 10 amperes. The remaining ranges are: from 0 to 200, 2000 microamps, from 0 to 20, 200 milliamps. In ordinary life, ten amperes are enough; when measuring current, the multimeter is connected to the circuit by connecting the probes to the desired socket, specially designed for measuring current. One day I first tried to measure the current in an outlet with my first simple tester model. I had to replace the probes with new ones - the standard ones were burnt out.

5 (fifth) sector. The icon looks like WiFi. 🙂 Setting the switch in this position allows you to conduct an audible test of a circuit, such as a heating element.

6 (sixth) sector – setting the switch to this position checks the serviceability of the diodes. Checking diodes is a very popular topic among motorists. You can check the serviceability of, for example, the diode bridge of a car generator:

7 - symbol Ω . Here resistance is measured from 0 to 200, 2000 Ohm, from 0 to 20, 200 or 2000 kOhm. This is also a very popular mode. In any electrical circuit there are the most resistance elements. It happens that by measuring resistance you quickly find a fault:

What is HFE mode on a multimeter?

Let's move on to more advanced functions. The multimeter has the following type of measurements: HFE. This is a test of transistors, or the current transfer coefficient of a transistor. There is a special connector for this measurement. Transistors are an important element; perhaps only the light bulb does not have them, but even there they will probably appear soon. The transistor is one of the most vulnerable elements. They burn out most often due to power surges, etc. I recently replaced two transistors in my car battery charger. To check, I used a tester and unsoldered the transistors.

The connector pins are marked with letters such as "E, B and C". This means the following: "E" is emitter, "B" is base, and "C" is collector. Typically all models have the ability to measure both types of transistors. With inexpensive models of multimeters, it can be very inconvenient to check soldered transistors because of their short, cut legs. And the new ones are the best :):). Let's watch a video on how to check the serviceability of a transistor using a tester:

The transistor, depending on its type (PNP or NPN), is inserted into the corresponding connectors and, according to the readings on the display, it is determined whether it is working or not. If there is a fault, the display shows 0 . If you know the current transfer coefficient of the transistor being tested, you can check it in the HFE by checking the tester readings and the transistor data sheet

How is resistance indicated on multimeters?

One of the main measurements taken by a multimeter is resistance. It is indicated by a horseshoe symbol: Ω, Greek Omega. If there is only such an icon on the multimeter body, the device measures the resistance automatically. But more often there is a range of numbers nearby: 200, 2000, 20k, 200k, 2000k. Letter " k" after the number denotes the prefix "kilo", which in the measurement system SI corresponds to the number 1000.

Why is there a hold button in a multimeter and what is it for?

Button Data hold, which the multimeter has, is considered useless by some, while others, on the contrary, use it often. It means data retention. If you press the hold button, the data displayed on the display will be fixed and will be displayed continuously. When pressed again, the multimeter will return to operating mode.

This function can be useful when, for example, you have a situation where you alternately use two devices. You have carried out some kind of standard measurement, displayed it on the screen, and continue to measure with another device, constantly checking with the standard. This button is not available on all models; it is intended for convenience.

Designations of direct current (DC) and alternating current (AC)

Measuring direct and alternating current with a multimeter is also its main function, as is measuring resistance. You can often find the following symbols on the device: V And V~ — DC and AC voltage respectively. On some devices, constant voltage is designated DCV, and alternating voltage ACV.

Again, it is more convenient to measure current in automatic mode, when the device itself determines how many volts, but this function is available in more expensive models. In simple models, direct and alternating voltage during measurements must be measured with a switch depending on the range being measured. Read about this in detail below.

Decoding the symbols 20k and 20m on a multimeter

Next to the numbers indicating the measurement range, you can see letters such as µ, m, k, M. These are so-called prefixes, which indicate the multiplicity and fractionality of units of measurement.

1µ (micro) – (1*10-6 = 0.000001 from unit);
1m (millies) – (1*10-3 = 0.001 from unit);
1k (kilo) – (1*103 = 1000 units);
1M (mega) – (1*106 = 1,000,000 units);

For example, to check the same heating elements, it is better to take a tester with a megometer function. I had a case where a malfunction of the heating element in a dishwasher was detected only by this function. For radio amateurs, of course, more complex devices are suitable - with the function of measuring frequencies, capacitor capacity, and so on. Nowadays there is a very large selection of these devices; the Chinese don’t do anything.

A multimeter is a universal portable device designed to measure various electrical (electronic) quantities. The multimeter can replace several devices, because It can be used to measure voltage, current, resistance, etc.

For example, the functionality of some multimeters additionally allows you to measure temperature, test transistors, semiconductors, etc. Many models of multimeters have a function that automatically turns off the display when the device is not active, and also has a backlight function.

Multimeters have long been used as portable measuring instruments both in production and at home.

Modern multimeters come in two types: analog and digital. When using an analog multimeter, the measured value is determined by the position of the arrow on the instrument scale. With digital multimeters, the measured value is displayed on a liquid crystal display in the form of numbers.

Digital multimeters are used in practice more often than analog ones. The main reason is the high accuracy of measurements and convenience in displaying the measured value. But analog devices also have their advantages.

To use a multimeter correctly, you need to know its basic structure and basic operating modes. Multimeters of different models may differ in size, appearance and number of measured quantities, but the basic functionality is the same for all.

The simplicity of the device, basic functionality and additional modes is demonstrated by the DT-831 digital multimeter.

Design and equipment of the DT-831 multimeter

At the top of the front panel there is a digital display, in the center there is a multi-position switch for measurement modes, and at the bottom there are three sockets for measuring probes.

When purchasing a multimeter, it is a good idea to know what is included in the package. Each product, including the DT-831, is supplied with two test leads, one 9V Krona battery, one user manual and a packaging box.

Multimeter functionality

Regardless of the type and type, any multimeter allows you to measure basic electrical quantities. This also applies to the DT-831 model.

Alternating current voltage is measured in ACV (alternating current voltage) mode.
DC voltage measurement is performed in DCV (direct current voltage) mode.
Direct current measurements are performed in DCA (direct current amps) mode.
Electrical resistance is measured in Ω mode.

For measurements, in addition to the main modes, additional modes are also used. For example, the semiconductor image is a diode test mode. Sound image – the mode of continuity of circuits with a buzzer.

The device is turned off by setting the multi-position switch to OFF mode.

Before measurements, the black probe is connected to a common socket marked COM (common), and the red measuring probe is connected to the VΩmA socket. Sometimes it is necessary to measure direct current with a value of more than 200mA. In this case, the red test probe must be connected to the “10A” socket.

How to use the DT-831 multimeter for dummies - Video

AC voltage measurement

In domestic conditions, voltage is most often measured in sockets, in adapter boxes, in distribution panels, in metering panels. The standard value of this voltage is about 220V. In production, alternating voltage is measured in switchgears, power cabinets, protection devices, etc. If in a household network the voltage is usually single-phase, then in production there is both single-phase voltage 220V and three-phase 380V.

The first measurement is made as follows. The multi-position switch is set to the maximum limit. For the DT-831 multimeter it is 750V. After this, the actual measurement is performed by connecting the multimeter in parallel to the element or section of the circuit being measured. For example, the phase voltage is measured relative to zero (phase voltage), or between two phases of a three-phase network (line voltage).

If the voltage value (and other values in a different measurement mode) is significantly less than the maximum limit (for example, 150V), then for greater accuracy the multi-position switch switches to a lower limit. In ACV mode this will be a 200V limit.

DC voltage measurement

In home living conditions, measuring DC voltage comes down to measuring the voltage of ordinary batteries, car batteries, and power supplies from household appliances. In production, DC voltage sources are rectifiers, DC generators, etc.

Measuring DC voltage is not much different from measuring AC voltage. The only difference is that the measurement in DCV mode is performed between plus and minus. In addition to directly measuring voltage, the DCV mode allows you to determine the polarity in DC circuits.

If the voltage value is known in advance before measurement (for example, a 1.5V AA battery), then the multi-position switch can be immediately set to the nearest limit (20V).

DC current measurement

This measurement is performed in DCA mode. A multimeter, like an ammeter, is connected in series to an open circuit. It is advisable to know the current value in advance in order to set the appropriate measurement limit.

How to measure resistance with a multimeter

Any multimeter model has a resistance measurement function. In Ω mode, you can measure the resistance of resistors, the value of electrical insulation resistance of wires, etc. Often in Ω mode they perform continuity testing of electrical circuits.

The DT-831 multimeter has five resistance measurement limits, ranging from 200 Ohms to 2000 kOhms (2MOhms). Resistance is measured by first selecting one of five limits.

If the measured value is greater than the set limit, “1” will be displayed on the multimeter display. In this case, it is enough to set the switch to a higher limit. If the display shows all zeros, then the actual resistance value is significantly less than the set limit and therefore the limit must be reduced.

Resistance measurements are only allowed when the voltage is turned off to avoid damaging the multimeter.