Multimeter: how much does the device cost, and what its price depends on, what is the difference between a digital tester and an analog one

A multimeter (tester, avometer) is a combined measuring device for determining current strength, voltage, resistance and other indicators necessary when working with electricity. How much a multimeter costs depends on its functionality. Even the simplest device with a minimum set of options is suitable for household needs, which are quite sufficient for to find out if the lithium-ion battery is working, and if the wire from the microwave ovens.

Varieties of devices

A tester with minimal functionality can simultaneously act as a voltmeter, ohmmeter and ammeter and it can be like a lightweight portable device designed to detect minor faults, and a complex stationary device. There are two types of multimeters:

• Analog. Often referred to as testers, avometers, or simply "Tseshki". They consist of a microammeter, a set of additional resistors for measuring voltage and conductors for measuring current. When measuring variable values, a magnetoelectric microammeter is connected to resistors through rectifier diodes. Measurement of resistances over 10 megohms is carried out using an external power supply. The devices are very popular due to their low cost (from 188 to 1000 rubles), but they have many disadvantages - a large measurement error voltages in high-resistance circuits, non-linear scale in individual operating modes, the need to convert units of measurement and the lack of automatic polarity detection connections.
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• Digital. The testers are equipped with a liquid crystal display, which displays the measurement results (in earlier versions, LEDs served as an analogue of the display). Among the advantages of digital devices, we can mention the measurement accuracy (typical error is ± (0.2% +1 unit least significant digit)), ease of use and the presence of additional functions such as a temperature sensor and meter frequency. The price of the device depends on its functionality: standard testers with a capacity of 3.5 cost 235-1600 rubles, and the cost of professional devices with a capacity of 5 and above can reach 9 thousand rubles. R.

How to choose a multimeter

Before purchasing an electrical tester, you should decide for what specific purposes it may be needed. If the device is necessary for household use (for example, checking the voltage in the outlet, batteries or power supplies), it is worth staying at the simplest models, and if it is planned to use it to carry out high-precision professional measurements, you need to select a more expensive device equipped with additional functions.

The main criteria for choosing a multimeter are:

• The way the results are displayed. Analog testers are best chosen by people who have the necessary knowledge to correctly configure the device and interpret the results. In the absence of experience with such devices, you should purchase a digital multimeter.
• The presence of auxiliary functions. Devices with extended functionality are much more expensive, but most of the offered additional options are not needed in everyday life.
• Measurement error. The smaller the error of the multimeter, the more accurate the results will be.
• Design and size. Sophisticated stationary devices are unlikely to be useful for an ordinary user, so for home use it is better to choose a miniature portable device.
• Protection from adverse factors. Testers that are not equipped with special protection are cheaper, but they easily fail when exposed to moisture or due to shock.
• Electrical safety class. CAT 11 devices are designed to determine the characteristics of power grids, CAT 111 are used to work with distribution circuits inside structures, and a multimeter should be purchased for outdoor distribution circuits class CAT 1V.

Features of operation

In order not to get confused during the first use, it is necessary to study the device interface in advance. Typically the front panel of a standard handheld instrument equipped with three sockets:

• COM - is used to connect the black wire, sometimes it is marked with a minus sign;
• 10A - designed for a red probe, required for measurements up to 10A;
• VRmA ("plus") - the red wire is connected to this connector when measuring all values, except for 10A.

Some models also have an additional connector for testing transistors.

In the central part of the electrical tester there is a round regulator, which serves to set the required measurement limits, dial mode and temperature determination.

In the operation of the device, the approximate measurement limits are extremely important, therefore, if any doubts arise, set the switch to maximum and take a measurement. If the obtained result seems too low, you need to move the switch to a lower value and repeat the procedure - its result will be more reliable.

To check the constant voltage (e.g. at the battery terminals) with an electronic tester, you need to do the following:

1. Set the switch to maximum (most often 750 or 1000 V).
2. Connect the wires to the connectors and measure. If the display shows a value less than 1000 V (for example, 12 V in a car wiring), set a lower limit of 20 V and repeat the procedure.

To check the health of the components of the electrical network, you should measure not a constant, but a variable value.

To get the last one necessary:

1. Connect the black probe to the minus connector and the red one to the plus jack.
2. Move the knob to the ACV position. When measuring the voltage in a typical outlet (220 V), the switch should be set to 750 or 600 V - if you set it to 200, the tester will fail.
3. Install the probes into the holes of the socket (the order does not matter). If everything is done correctly, the display will show the measurement results in volts.

The principle of operation of an analog device is similar to a digital one, but before use it should be calibrated by setting the arrow to zero with using the head located under the scale, and when switching from smaller units of resistance to large ones and vice versa, it is necessary to use the variable resistor.

Security measures

The operation of any electrical tester consists of three stages: correct connection of the wires, setting the regulator to the required position and measuring with correction. When working with all types of multimeters a number of precautions must be observed:

• Having selected the measurement range and setting the permissible limits, you should install the test probes in the appropriate connectors. The operating mode is set before connecting the probes to the electrical circuit and is not changed at the moment when the wires are under load - this will lead to a breakdown of the device.
• If the approximate limits of the measured value are unknown, it is necessary to start with a larger value (except when measuring resistance).
• When measuring voltage from 60 V, do not hold on to the test leads with both hands, as you can get an electric shock.
• When measuring voltages from 380 V, the test leads should be replaced with high-voltage ones, which are equipped with special anti-slip stops.

Voltage testers are universal devices that help to identify a breakdown of a household electrical appliance or an electrical network connector in a few minutes.

If you choose the right multimeter and strictly adhere to the instructions attached to it, the use of the device will not cause any difficulties for the user.