How to measure voltage with a tester. How to use the tester - types of measurements and their features

All about protection devices
10.08.2019

A tester, or multimeter, is a device for determining voltage, current, resistance and other indicators necessary when working with electrical networks and devices. At home, it allows you to determine if the outlet is working, if the wire from the computer is damaged, and if the battery of a smartphone or other gadget is working. Even a simple device with a minimum set of functions is suitable for domestic needs. For accurate measurements, manufacturers offer improved models.

There are two types of devices that measure the characteristics of electrical networks - analog and digital.

The analog voltage tester is equipped with a magnetic needle and measuring scales, next to which the values ​​\u200b\u200bof the values ​​are signed. The popularity of the device is due to the low price - they buy it, despite the shortcomings:

  • the need to convert units in the measurement process;
  • small divisions and signatures on the scales;
  • inaccurate results due to fluctuation of the needle.

Mini tester for home

To fine-tune the tester, a tuning resistor is provided that allows you to set the arrow to zero.

The digital instrument is equipped with a liquid crystal display, which shows the measurement results. In early models, instead of a display, the result was shown by LEDs. The advantages that the meter has: the tester gives a result with an accuracy of 4.5 digits, it is easy to use and does not require knowledge to convert values.


Analog instrument

Other positive aspects:

  • additional functions - temperature sensor, frequency meter;
  • animated scale on the display to measure fluctuations.


Digital tester with display

Interface and wire connection

Learn the interface so you don't get confused about how to use the DIY measurement tester. The front panel of the simplest device has three outputs (connectors) for connecting wires and four measurement areas.

Tester connector designations:

  • COM or "-" - common, for connecting a black wire;
  • 10A - for connecting a red probe when measuring current up to 10 amperes;
  • VRmA or "+" - to connect the red wire when measuring other quantities and any current, except 10A.


Multimeter outputs

There can be four connectors - then they are usually graduated as follows:

  • 10A or 20A;
  • mA - for measuring current in milliamps;
  • COM - to connect the black wire;
  • VΩHz - for other measurements.

Some models have an additional output for testing transistors.

In the center of the tester there is a round switch designed to set the measurement limits in at least four areas:

  • DCV (V=) – constant voltage area, allowable measurement limits – 10, 20, 200, 1000 V
  • ACV (V~) - area AC voltage, limits - 200 and 750 V
  • DCA (A=) - DC current measurement in the range from 0.5 mA to 500 mA;
  • Ω - resistance, limits - 200 Ohm - 2 MΩ.


Front panel and scheme of using the device

Additionally, the switch of the tester can be moved to the positions:

  • 10A - for measuring current, up to 10A;
  • Temp - to determine the temperature;
  • Hfe - for testing transistors;
  • Ringing - to determine the gap electrical circuit.

When using a tester, it is important to know the approximate measurement limits. If in doubt, set the switch to the maximum value and take the first measurement - the device will show an approximate value. If it is low, move the switch to a lower value and repeat the measurement - the result will be more accurate.

Example: to measure the voltage in electrical network, set the switch to ACV 750V and connect the probes to the socket. Seeing the value of 160V on the display, switch the tester regulator to the 200V position and repeat the measurement.

How to use a multimeter

Using a multimeter includes three main steps: connecting the wires, setting the regulator to the desired position, and measuring with correction. Any characteristic of the electrical network is measured according to a given principle.


Tester at work

How to measure DC voltage

Constant voltage is created by batteries, power supplies, galvanization. They feed the equipment, and when it fails, the first thing the master checks is the voltage at the battery contacts.

How to use the tester for self-checking DC voltage:

  1. Set the switch in the DCV area to its maximum value, usually around 750 or 1000 V. You will see an excessive voltage warning on the display - be careful if the numbers are too high.
  2. Connect the black wires to the COM output and the red wires to the VRmA output.
  3. Take a freeze. If you see a value less than 1000V (for example, 12V in automotive wiring), set the lower limit to 20V.
  4. Repeat the measurement - you will see the updated numbers on the display.


Switch set to V= position for DC voltage measurement

Limit designations on the tester:

  • 200m - up to 200 millivolts, that is, 0.2 V;
  • 2000m - up to 2 V, for example, on a galvanic cell;
  • 20 - up to 20 V, in automotive wiring;
  • 200 - up to 200 V;
  • 1000 - up to 1000 V.

How to calculate AC voltage

AC voltage is often required to be measured in order to determine the health of an outlet or other electrical element in an apartment.

How to use an electrical AC voltage tester:

  • Connect two probes to the device - black to the COM connector, red to the VRmA connector.
  • Set the knob to the ACV position.
  • Knowing that the voltage in a standard outlet is approximately 220 V, set the switch to a higher value - 750 V or 600 V. Do not turn the knob to 200 - the device will “burn out”.
  • Install the probes into the outlet holes in any order. On the display of the tester you will see the measurement result in volts.


Checking the outlet with an ammeter

How to determine the resistance of a conductor

You can measure the resistance across a resistor using the Ω region. The limits of values ​​are large - from 200 Ohm to 2000 kOhm (= 2 MΩ).

Measuring range:

  • 200 Ω;
  • 2000 Ω;
  • 20k;
  • 200k;
  • 2000 k - the result is displayed in kiloohms.

How to use a tester-multimeter to determine the resistance:

  1. Connect the probes and select the Ω area.
  2. To set the measurement limit, look at the marking of the resistor. For example, element 1K5 must be measured within 2000 Ohms, and 560K - within 2000 kOhm.
  3. If the resistance value is unknown, set the regulator to a lower limit.
  4. If the resistance is greater than the selected limit, you will see the number 1 on the display. Gradually increase the limit until a valid value appears instead of one.


Multimeter connection diagram for measuring different values: current, voltage and resistance

In most models, it is possible to measure only direct current, but in some cases there is a mechanism for switching probes for measuring alternating current.

How to operate the DC current tester:

  1. Set the regulator to the DCA or 10A position (when measuring current up to 10 amperes).
  2. Connect the probes: black to COM, red to VRmA or 10A.
  3. Select the measuring range from 200µ to 200mA.
  4. Connect the probes in series to the electrical circuit. You will see the current value on the display.

How to perform dialing with probes

Continuity mode - a function that allows you to check for breaks and short circuits in the circuit.

How to use a voltage tester in continuity mode to check the integrity of the connection:

  1. Set the regulator to the appropriate position. It is usually indicated by a symbol resembling a speaker or a sound wave.
  2. Connect the wires with probes to the device.
  3. Attach the probes to the edges of the ringed section of the circuit, after turning off the power.


Dialing diagram without a sound signal using a light bulb

If the circuit is closed, then at the moment the probes touch, you will hear a sound signal, which will not be in the presence of a break.

Checking diodes for performance

The diode passes current in only one direction, respectively, the probes must be connected in a given sequence. When connected in the opposite direction, no current will flow.

How to use a voltage tester to determine the health of a diode:

  1. Connect the test leads to the instrument.
  2. Set the switch to diode test mode.
  3. Connect the black wire (negative) to the cathode and the red wire (positive) to the anode.
  4. On the display you will see the value of the breakdown voltage - on average, 100-800 mV.
  5. Swap the wires and check the result. If the value is not greater than one, the diode is good. Otherwise, the diode passes current, and the indicators for both connections are equal to one. This means it is defective.


Diode test circuit

Similarly, you can test the LED - it is easier to work with it, because a working element lights up when the test leads are connected.

Checking transistors p-n-p and n-p-n

You can check the health of the transistor with a multimeter in the ohmmeter mode - a resistance meter. In this case, consider the transistor of the form “n - p - n” as diodes connected in opposite directions. Sequencing:

  1. Connect the wires to the tester and set the regulator to the desired position in the Ω region.
  2. Connect the red wire to the base terminal using an alligator clip.
  3. Connect the black probe in turn to the remaining terminals - the collector and emitter.
  4. The values ​​on the display will be the same as when testing the diode.

If you swap the red and black probes, then the value on the screen will become equal to one, which indicates the health of the transistor.

To finally make sure that the element is working, ring the transitions "collector - emitter", "base - emitter" and "collector - base". The screen should show one.

Check the "p - n - p" transistor in the same way, initially swapping the positive and negative probes.

Video: How to use the tester correctly

Features of using an analog device

The principle of operation of an analog multimeter is the same as a digital one, but there are several fundamental differences in operation.

How to use the arrow tester:

  1. Calibrate the device - set the pointer to zero by turning the knob located under the scale.
  2. To measure voltage, use the buttons to select AC or DC.
  3. When measuring resistance, moving from smaller units to larger units and vice versa, use a trimmer.

The remaining settings are the same as the settings for the digital tester - plug the wires into the connectors in accordance with the measured value, and set the regulator in accordance with the measurement limit.

How to work with a tester or analog type multimeter, on which scales to take readings:

  • constant voltage - black scale, V, mA;
  • alternating voltage - red scale 10V AC or black scale, V, mA, depending on the selected limits;
  • resistance - green scale, Ω;
  • direct current - black scale VmA;

Some models of analog testers allow you to measure dB readings and test batteries. The battery status is determined by the red or green scales, and the dB parameters - by the red.

When working with an analog tester, the question may arise - how to position the device itself at the time of measurement, because the readings depend on the position of the arrow. To properly place the device, look at how the support legs are located on the case.


Wires for a multimeter with nozzles

Rules for using voltage testers

There is a set of rules that must be observed when working with a tester of any type - these are safety rules.

  1. After selecting the measurement range and tolerances, install the test leads in the appropriate sockets.
  2. Set the operating mode of the device before connecting the probes to the electrical circuit. Do not switch the mode if the wires are under load - this will lead to breakage.
  3. If you do not know the approximate value of the measured value, start with a larger value (the exception is resistance measurement).
  4. When measuring voltage from 60 V, do not hold the probes with both hands - there is a possibility of electric shock.
  5. When measuring voltage from 380 V, replace the test leads with high voltage ones equipped with anti-slip stops.


Pay attention to specifications

How to choose a tester for home

Determine what you need a tester for - an electrical multimeter can be highly accurate or have a set of additional functions. But in everyday life these opportunities are rarely used.

How to choose a multimeter tester - the main criteria:

  • digital or analog way to display results;
  • availability of additional sensors and functions;
  • measurement error - from 0.025 to 3%;
  • design and size;
  • protection against moisture and shock;
  • electrical safety class: CAT 11 is suitable for characterization in power networks, CAT 111 for working with internal distribution circuits inside buildings; CAT 1V for distribution circuits outside buildings;
  • manufacturer.

Voltage testers are universal devices for working with electrical and electronic devices, allowing you to determine the breakdown in a few minutes. After reading the instructions, its use is not difficult. A device for the home costs between 300-500 rubles, you can buy it in radio and electrical stores.

The tester, or avometer, multimeter, is designed to determine the constant resistance, direct and alternating voltage. Some models also make diode continuity, measure temperature, and determine the capacitance of condensates.

What is a tester?

This is a small rectangular device, in the center of which there is a handle for determining the measurement mode, it can be rotated 360 degrees, it can be used to make a dial tone, measure voltage, and also turn off the device. Before using the tester, it is important to know all the conventions. All measurements are combined into several groups: ACV, DCV, DCA.

The first two letters indicate in which form of current the measurements are taken: direct or alternating. AC - circuit alternating current, DC - constant. The third letter is the units of measurement: V - volts, A - amperes.

How to measure voltage correctly?

Before proceeding with the readings, it is necessary to make sure that the device is correctly connected and nothing prevents its operation. First you need to check that it contains an undischarged battery.

In total, the tester has three pinches: one is used to measure voltage, resistance and current in milliamps, the second must be connected to the COM connector, and the third is connected only if the mode is selected high current. It will help you learn how to use the tester, a video that details the structure of this device and the rules for connecting and measuring.

Step by step instructions for measuring

To measure direct or alternating current, you need to measure the potential between two points. For example, if you measure the voltage in a resistor, then two pins of the tester are connected to it.

Before measuring, you need to make sure that the pliers are firmly and correctly connected to the device, then set the required mode, while observing some rules. To measure the voltage, the pins are connected in parallel with the load, the resistance indicators are directly at the place of its occurrence, if this did not happen in the network, the current - in the breaks of the conductors.

To practice and learn how to use it correctly, you can first measure the voltage in a finger battery. To do this, you need to know that its value is 1.5 V, so it’s better to choose DCV 20 on the tester, and then touch the contacts with probes. The measurement result should appear on the display almost immediately. If it is unknown, then you need to change the measurement parameters, increase or decrease them, it depends on the specific situation. For a home network, the initial indicator should be set to ACV750 V, that is, more than 200, carefully connect the probes and look at the result.

How to measure current correctly?

Current is measured differently than other indicators. For this, three probes are used. For example, to measure the current level in a flashlight, one probe is connected to the battery contact, the second to the opposite contact, the third probe to the other connector. First, the maximum value is set, then it must be gradually reduced.

To find out the resistance, you need to set the maximum value on the device and gradually reduce it.

Diode continuity

This is another function that the tester performs. The ringing mode can be turned on if you set the knob to the appropriate sign of the diode. Such measurements consist of two stages: first, the red wire is connected to the ends of the diode, first on one side, and then on the other. The infinity sign should appear first, followed by the number in millivolts. The exact figure is obtained only when the red wire is connected to the anode. In this mode, you can not only make a call, but also pinout bipolar transistors. It is carried out in three stages:

  1. First, the red wire of the device is connected to the transistor contact.
  2. The second probe must be connected in turn to one, then to the second contact. Actions are performed until the exact numbers appear on the display.
  3. If all actions do not lead to accurate indicators, then the algorithm must be repeated again, first disconnect everything and connect again, you can also swap the wires, that is, connect the black wire to the contact, and try to make measurements with the red one.

Using the tester in a car

The tester can also be used to read data in the electrical networks of a car, determine the status of contacts, crankshaft rotation, and circuit resistance.

Most often, they are interested in how to use a voltage tester in a car to measure readings in a battery. You need to know that for this you need a device that has a voltmeter scale with limits of 9 -15. To do this, you need a source of reference resistance - a stabilizer and a resistor. The first one is powered by a battery.

The tester is designed to measure voltage, resistance and current. To learn how to use it, you first need to practice on conventional instruments, the readings of which are precisely known.

Any home master who has at least basic knowledge in the field of electrical engineering should know how to use a multimeter (tester). Despite the fact that a modern device has a lot of functions, capabilities and measurement limits, it is quite simple. The main thing is to learn how to connect the measuring probes correctly, understand the meaning of all the symbols printed on the front panel and be able to work with different ranges and modes depending on the situation. To understand the details of this issue, we suggest using the following instructions for using testers in practice. As an example, in this article we will consider a digital device, which will be much easier to work with compared to a pointer multimeter. If you have not yet purchased the device, be sure to check out our.

What is important to know about the tester device

Before starting any electrical measurements, it is worth understanding what the device itself is and what its functions are. All information is printed on the front panel. You can learn how to use the multimeter of the selected model based on the following generally accepted notations:

  • ON / OFF - button on / off the device (on some testers it may be absent, the device will be turned on in this case by turning the range switch);
  • DCA (or A-) - direct current;
  • ADCA - alternating current;
  • ACV (V ~) / DCV (V-) - AC / DC voltage;
  • Ω is resistance.


To take readings, you need to use the rotary switch, which allows you to set various modes of operation of the multimeter, select the measurement range.

One of the important points in mastering the question of how to use a digital multimeter is the correct connection of test leads to the appropriate connectors. The correctness of the measurements performed will depend on this. In order not to make a mistake, there are simple rules:

COM - black size on the left, universal connector in the center, high current connector on the right

  1. the COM connector is common, it is used to connect the negative black test lead;
  2. to connect the red positive probe, one of the sockets for measuring voltage (V), resistance (Ω), current (mA, A) can be used, while it should be borne in mind that, as a rule, there are two current sockets (for working with low-current circuits and with current up to 10/20 A, depending on the model of the tester).

But it is also necessary to take into account that when measuring voltage or current, the measuring probes installed on the contrary will lead to a change in the polarity of the received data, which will be reflected on the display by the appearance of the “-” sign. Numeric values ​​will be correct. This is where digital devices differ from analog devices. In the latter, the arrow most often goes beyond the scale, and in some cases such work can damage the device.

Instructions on how to use a multimeter for dummies

The main purpose of any tester is the measurement of electrical quantities. When measuring current, the device connected to the circuit is connected to an open circuit (in series), and in order to use the tester as a voltmeter, it is connected to the circuit in parallel.

Using a digital multimeter to measure voltage

The technique for measuring DC voltage is quite simple.

  1. Using the rotary switch, we select the type of the measured value and the measurement limit.
  2. The setting of the limit can be done after the user decides what the approximate value of the measured voltage is. A hint can be the markings on the batteries or parts of electrical circuits. The limit must always be greater than the measured value in order to prevent overloading of the device elements and its failure.
  3. In accordance with the instruction manual, the measuring probes must be connected to the terminals / terminals (black - to "minus", red - to "plus").
  4. We get the value of the constant voltage on the display of the tester.


measure the voltage of the electrical network

Another way to determine the measurement limit is to initially set the connected device to the largest possible measurement limit. Then, taking readings to improve the accuracy of the data obtained, you can reduce the limit to the nearest higher value, comparing it with the measured readings. There are no fundamental differences in how to take data on direct and alternating voltage. The only difference is to switch the tester to the desired mode. Then the above algorithm works.

Practical example of using the voltage measurement function

One of the most common operations in which you need to measure the voltage is to check the condition of the batteries. Moreover, it can be both ordinary finger and automobile. In any case, it will not be superfluous for the home master to know how to use the multimeter correctly in such a situation. If we are talking about finger batteries, the measurements are performed as follows: the switch is set to the desired DC voltage limit. The resulting value must correspond to the nominal value. A deviation of ±10% from the nominal value is considered normal.

How to measure current

Before using a tester (or multimeter) to measure the current strength, it is necessary to determine whether the device under study works with a variable or direct current. In addition, you need to know the approximate value that will be obtained as a result. This will allow you to correctly select the mA or 10/20 A socket used for operation. Even if you have no idea even approximately what current you will get in the end, solving the problem is simple. It is enough to start by setting the maximum limit, and then, focusing on the data obtained, if necessary, re-measure the value by moving the measuring probe and switch to a smaller range.

Continuity testing with a multimeter

Circuit continuity is one of the main modes that is often used in domestic use of multimeters to determine open or short circuits in a circuit. It is enough just to set the desired mode on the tester, turn off the power (including such low-power ones as batteries), discharge the capacitors, install the measuring probes and connect them to the desired points of the electrical circuit.

For the convenience of the user in the absence of breaks in most models, a buzzer is provided, the signal of which makes it easy to navigate the results. In addition, the display in this case will show the value of the resistance or "0". The absence of sound or the display of "1" on the screen will mean an open circuit in the circuit under study. You can find out more about the continuity of wires, switches and other devices in.

Resistance measurement

A huge “plus” of the resistance measurement operation itself will be that when measuring it using a multimeter, it is almost impossible to damage the device or part in the equipment being repaired. To perform the operation correctly, you need:

  1. set the rotary switch to sector Ω,
  2. turn off the power, remove the batteries, accumulator,
  3. choose the most suitable measurement range,
  4. connect to the terminals of the measured circuit element,
  5. take readings.


The whole procedure is fairly standard. The only important difference is that after taking measurements, you can see "OVER", "1" or "OL" on the display. This means that an overload has occurred and measurements must be repeated by switching the device to a larger range. Also, the display may show “0”, which means that the limits need to be lowered. To successfully use the resistance measurement function, knowing these simple rules will be enough.

Capacitance measurement

Radio amateurs and electricians involved in the repair of household appliances often need to measure the capacitance of capacitors. This issue is no less relevant for the owners of machine tools, who periodically need to select the capacitance of capacitors when connecting a three-phase motor to a single-phase network to optimize the operation of the motor. These operations are performed by analogy with the measurement of resistance.

An important difference is not only the position of the switch, which must be set to the appropriate mode and range, but also the mandatory pre-discharge of the capacitors. Otherwise, at least incorrect readings will be obtained (when working with low-capacity elements), and at most, the device will fail. As a rule, manufacturers provide separate sockets in the multimeter for operation in capacitance measurement mode.

Detailed video instructions

In the first part of the video you will find general information on how to use a multimeter and learn how to measure DC and AC voltage.

After watching the second part, you will learn how to measure resistance, ring circuits, test diodes, use the built-in generator, and also measure the magnitude of electric current.

Safety when working with a multimeter

There are several potentially dangerous situations in which simple user inattention can lead to damage to the instrument and failure of the equipment under test.

  1. If it is necessary to measure the voltage, while the probes are installed correctly, and the switch is in any position other than voltage (on resistance, current).
  2. If you need to measure current, the test probe is installed in the socket for measuring low current circuits, and the switch will be set to measure high current.
  3. When dialing or measuring resistance in the equipment, it is necessary to remove all batteries installed in it, since operation in this mode will disable the device.
  4. When operating in the continuity mode, if there are charged capacitances (capacitors) in the circuit, it is necessary to discharge them by short-circuiting. When operating circuits with high-capacity elements, discharge can be performed through an incandescent lamp. Ignoring this rule may cause the multimeter to burn out.

All of these situations lead not only to material losses, but also to increased danger for the person working with the tester. If you use the multimeter incorrectly, working with electricity can lead to accidental contact with live parts under high voltage and that is life threatening. Otherwise, it is enough to follow the simple rules and laws of electrical engineering in order to easily master the work with a multimeter in all its modes and successfully carry out the necessary measurements without contacting specialists.

Every electronics lover has this small but very capable device, so we will tell you how to use the tester based on the experience of one of our friends. But first, let's figure out what it is, and what parameters we can analyze with this tool.

1 Multimeter and cable tester - what's the difference?

A tester is a rather comprehensive concept, it includes both a familiar multimeter and a cable tester that checks the integrity of the wire along its entire length and can even indicate the location of an open circuit. A multimeter, as its name implies, can do a lot. Its main functions include the determination of voltage, resistance and current strength, which corresponds to separate devices voltmeter, ohmmeter and ammeter. It can be portable and stationary, and its scale can be analog or in the form of a digital display.

The cable tester also differs in its purpose. There is a state meter optical cables and twisted pair (network). The second type also includes a telephone and coaxial cable meter. At the output, we can get the following parameters: wire length, wiring diagram, degree of pickup and attenuation, resistance and losses. By class, devices are divided based on their reliability. There are basic (read household, for simple verification), with a qualified degree of verification and a certification level.

They differ not only in accuracy and reliability, but also in functions. For example, a certification tester has the ability to diagnose and find the causes if your wiring fails the test, that is, is faulty.

2 Cable tester and multimeter - measurement features

Before using a voltage or cable tester, you should know what to expect when we connect the device. It is also important to remember how to use it correctly. Otherwise, we can not only get incorrect results or not see them at all, but also cause a fire or an unpleasantly smelling melting of the wire insulation. For a multimeter, it is important that it measures what he personally feels, that is, "measures himself." This means that we need to pass all the parameters of interest to us in full through the device.

How in one case or another it should be connected to the circuit, we will be told the laws of school-level physics, but we will mention this below. The cable tester is not capricious in terms of connection, since it is usually impossible to confuse the connector with it. To work with it, you only need to understand how to recognize certain signals, but it is better to read about this in each specific manual for the device, in fact, as well as about the signals that its display shows. Before work, you just need to find out in which speed range the cable should work, and then measure whether the actual value matches the expected one.

If the value does not match, then diagnostics are needed by a certifying tester, it is important to carry it out in the NEXT mode (induction at the end of the cable) and Return Loss (losses on return). Then you can determine what is wrong - the cable itself or its connectors.

3 How to use the tester for various measurements?

Regardless of whether your tester is electrical or analog, you should know the general approach to measuring the most common parameters.

DC and AC voltage

To measure this parameter, you need to switch the tester to the voltmeter mode, to do this, find the designations DCV (V) and ACV (V ~), these letters denote constant and alternating voltage, respectively. According to physical laws, the voltage value should be taken when the device is connected in parallel, only in this way there will be a potential difference on it, as in the main circuit.

There are several features in this whole process. For example, your readings will not be accurate if the resistance of the measured section of the circuit is about 1 MΩ, because the tester's own resistance in this mode is very high, and it will give an underestimated result. Thus, for the reliability of the results, it is necessary to observe the condition that the source current be much greater than the ratio U / R, where U is the desired voltage, and R is the intrinsic resistance of the measuring device.

But that's not all, when measuring ACV, the device rectifies it using diodes, but they also have their own potential difference, which gives an error when measuring AC voltage in the region of 1-3 Volts, the value will simply be underestimated. In the same way, the device will lie in the case of measuring a voltage drop of a high frequency, and the threshold is not so high, the values ​​\u200b\u200bwill begin to differ from the real ones already in the region of a couple of hundred kHz.

D.C

Again we return to school physics, so that the same number of charges pass through the device as through the analyzed circuit, it must be connected in series, that is, wedged into it (into a circuit break). The mode is called DCA, and for high values ​​there are functions 10A and 20A. True, do not forget to replace the standard wires with reinforced ones for these modes, because the standard ones do not hold such loads and melt, or even burn, because they are designed for a maximum of 5 Amperes.

But the alternating current cannot be directly measured, you can only pervert by connecting a resistor with extremely low resistance to the circuit. The current is already measured on this element of the circuit, and then the desired current value is found by the formula U / R, only the error of such a measurement is quite large, and then the method works in case of extremes - either very high current or very low.

Resistance

This value is measured on the resistor when the circuit is off, that is, the current should not flow. The ohmmeter mode in the tester is switched on through the designation with the letter "Omega" (horseshoe). If you still do not block the current in the circuit, you will get a value that cannot even be used for calculations, since the resistance of the remaining part of the circuit will play against the resistance of the resistor, which, by the way, is unknown. But the differential resistance of some elements (nonlinear) cannot be obtained using a tester either, only indirectly, and you will have to not only count, but even build graphs U = f (I), after changing the analyzed circuit.

Diode ringing

The mode is activated by the corresponding icon, which depicts a diode. Cannot be used with power on. We take the red wire and bring it to one end, and then to the second. The one from which the digital value will be shown is the anode. If the infinity sign is on the screen, then you have stumbled upon the cathode.

Transistor pinout

The tester works in the diode ringing mode, we attach the red wire to one of the ends of the resistor, with the second wire (black) we check the contacts (both). If the display gives us two numbers, then this npn transistor. The numbers will be almost the same, but remember them, or rather note in which case the value was less. Now you can define the base, emitter and collector: the first object is the contact for which we hold the red wire, the second is the one for which the figure was greater, and the last one for which the figure was less.

If the reception with the red stationary wire did not give us any values, then we disconnect the red wire and permanently fix the black wire, and check the contacts with red in search of numbers on the screen. So we select a combination with adequate behavior. If the black wire is lucky, then the transistor is p-n-p type, and the emitter and collector are calculated according to the same pattern.

Capacitance and inductance

In some models of testers, there may be functions for measuring the numerical value of these parameters, and the modes C (capacitance) and L (inductance) are indicated. Connect like an ohmmeter. If there are no special modes, then the presence (operability) of these characteristics can be established using the ohmmeter mode, but you will not get a numerical expression. How to determine this: the resistance of a good coil should tend to zero and be expressed by some small finite number, and the capacitor, on the contrary, its resistance should be very large, up to infinity. When connecting the electrolytic capacitor to the tester, observe the polarity (red - to plus, black - to minus), and do not try to grab the leads with your hands.

During a planned power outage or during an emergency power interruption, it is sometimes necessary to verify the presence of electricity in the local network. An electronic voltage tester or a current probe, which can replace an expensive multimeter, will help check this.

What it is

An electrical tester is a device that is used to measure and determine the voltage in an electrical circuit. The main difference from the multimeter is the simplicity of design and use of this unit, it works quickly and can be used in any conditions.

Photo - resistance tester

There are also more compact probe testers that can measure the voltage level in an outlet or any other electrical device, for example, generators in a car. They differ from standard indicators in their small size, they also have simpler instructions for use.

Kinds

Previously, a pointer tester, such as ASCOM, was mainly used. Him reliable circuit work, it is powered by batteries and provides a fairly reliable and accurate operation.

There are several types of such screwdrivers:

  1. Plain, neon;
  2. LED;
  3. Universal.

Plain is the most common and affordable, but by no means reliable, it is not replaceable for urgent home wiring repairs. It consists of two working parts - a contactor and a handle. A contactor should be understood as a conventional screwdriver, which is connected to a wire outlet or a socket. On the handle is another part - zero, as it is sometimes called by electricians. For correct definition voltage, it should be in contact with the thumb. If, when you touch the neon tester, the signal light starts to glow, then there is voltage in the network.


Photo - professional index

LED a screwdriver works in a similar way, except for the need to touch the contact on the handle. It is safer because it can be handled with gloves on. Using such an indicator, you can also determine the zero or phase cable. To do this, bring a screwdriver to the outlet of the network and touch the contacts to the bare wires or socket. If the lamp lights up when the electric current is on, then you are in phase, if no changes have occurred, then to zero.

Some models of LED voltage testers allow you to perform non-contact analysis, i.e., measure the current of a power consumer without touching open contacts with a usb connector screwdriver. For such a test, the device is brought to the insulation, and in the presence of voltage, the signal lamp starts to glow. This is very convenient for circuits where voltage and resistance are high.


Photo - stayer indicator

Multifunctional electrical network voltage tester type Stayer (Stayer) is a universal indicator that allows you to measure the resistance, voltage and strength of direct or alternating current in the network. The main advantage is that 3 modes of operation can be used for testing: contact, non-contact and sound (with non-contact dialing at high sensitivity of the measured devices). This digital electronic indicator is equipped with a very comfortable wide handle, on which the operating mode switches are located. There can be several of them, in accordance with the number of measurement types, so this voltage tester can be used in any conditions.

In most cases, pointers can be switched in the following order:

  1. 0 - work through a contact connection;
  2. L - non-contact type;
  3. N - non-contact operation at high sensitivity rates.

The device is equipped with a special protection made in the form of a cap that hides the working part. Any universal tester also has a contact on the handle, when pressed, you can determine the location of the circuit break. His work is the most reliable and accurate.

Video: VTTEST5 tester

Stamps

You can buy a voltage tester at any electrical goods store, where you can also repair devices if necessary. Consider the technical characteristics of the most popular models.

This is a very handy Chinese pocket detector, like the Uni-T, which is equipped with a fairly large liquid crystal display. Its feature is that the device can be used as a multimeter, the main thing is to ensure that its contacts are intact.

Fluke T90 Probe Tester:

HAUPA Profi household tester:

In addition to the ability to measure voltage, you can determine the polarity of the phases, which is necessary when repairing or wiring. Many Chinese models do not have warranty period, therefore, for constant and reliable use, we advise you to pay attention to domestic or European indicators. They are a little more expensive, but will last longer.

MS-18S Svetozar (for low current):

Greenlee NETcat Micro NC-100 with pliers and contact screwdriver:

Mastech MS8222H (similar to American DT-830B):

The price for each voltage tester depends on its parameters, the cost varies from 500 rubles to several thousand. Good reviews about indicators like Sparta, Resanta, USB GT-95E, VRT-325, battery, TN - 600 and VDE. Sale is made in all cities of Russia and Ukraine (Moscow, Yekaterinburg, Kharkov).


Photo - USB indicator

When buying, be sure to check the quality certificate and the provided warranty period. Then you can count on a warranty repair in the event of a device breakdown.