During electrical work, there is always a need to measure electrical characteristics: amperage, resistance and voltage. It is convenient to carry out measurements of these values using a tester, which must be present in the arsenal of a good host. The article will consider such a device as a multimeter: which one is better to choose so that it meets the stated requirements, is easy to use and has an affordable price.
Multimeter: which one is better to choose on the basis of technical characteristics
Every owner should have a device in the house that will measure all kinds of electrical parameters. It will help detect a broken wire, find out the voltage in the battery or outlet, check the integrity of the heating element, lamps and other electrical components.
Choosing a multimeter, you should be guided by the characteristics that are needed to solve specific problems. The installer is quite enough for a simple tester to measure voltage, check the resistance and ringing the circuit. For an electrician, whose job is to maintain electrical equipment, the “current clamp” function will be useful, allowing you to measure the load while the equipment is running, without interfering with the circuit. This will prevent accidents.
Instrumentation masters will need the following functions: voltmeter, ohmmeter, ammeter, frequency meter, inductance meter and capacitance meter.
The device should not only be equipped with the necessary functions, but also be easy to use. For permanent use, you can choose a pocket digital multimeter, which is slightly larger than a conventional lighter. If the work is carried out in one place, then it is better to choose a larger device that will also transmit more accurate readings.
The choice of a multimeter comes down to the main criteria:
- device type;
- functionality of the device;
- work errors;
- design features;
- degrees of protection against dust, moisture and other influences;
- electrical safety class of the device;
- manufacturer.
All multimeters regardless of the type of device perform the same range of tasks. However, when determining which multimeter to choose, one should know and take into account all the advantages and disadvantages of a particular device model.
Testers are divided into two types:
- digital (electronic);
- analog (switch).
Electronic tester is ideal for solving household tasks. It is easy and convenient to work with him, because reading the readings displayed on the display is not difficult, as shown in the photo. Choose a digital multimeter, the price of which varies depending on the functionality of the device, it is possible in specialized stores, where various models are presented. Accurately determine the reading on an analog multimeter is more difficult, because it varies depending on the angle at which they look at the arrow.
With a needle tester, it is easier to work with a professional electrician, who must track the dynamics of changes in the electrical circuit performance. The digital multimeter has no such function. However, it has many other features that the switch multimeter is not equipped with. Depending on this price is formed. You can buy a digital multimeter, ranging from 240 rubles.
To measure indicators on a digital device, it is not necessary to observe the polarity. If the display shows a “-” in front of the number, then the tester was connected in the reverse order. On the arrow multimeter without polarity, the arrow deviates from the scale.
The battery charge of the electronic multimeter is consumed during all measurements that are true until the battery is discharged. In analog, energy is conserved when measuring voltage and current. However, the arrow starts to deviate from zero only depending on the low battery.
Helpful advice! If it is necessary to fix the dynamics of measurements, but there is no desire to work with an inconvenient scale for reading the results, you can purchase a tester with a display and an arrow.
Determining which multimeter is best to buy, reviews of which can be read on the Internet, should be guided by its functional features. After all, each new function affects the cost of the tester.
All testers are equipped with the main features:
- direct current measurement;
- AC change;
- check of alternating voltage in the network up to 700 V and constant in the circuits;
- ringing the circuit and checking the integrity of the state of the contacts;
- measurement of the resistance of conductors.
Some models of testers can be equipped with the following specific capabilities (more often it refers to digital devices):
- the ability to check semiconductor devices;
- measurement of frequency and temperature;
- capacitor capacitance measurement;
- test signal generation function;
- power off timer;
- automatic backlight display;
- automatic determination of permissible limits of measurements;
- fixation function.
One of the most important characteristics of this device is the accuracy of all measurements, which is determined in the error of the device. This indicator should be in the range of 0.025-3%. Multimeters for domestic purposes can be selected with an accuracy of 3%, and for professional purposes it is better to choose the most accurate devices. This indicator will affect how much a multimeter costs. The price of a more accurate instrument will be no less than 800 rubles, and a simpler one will cost 240 rubles.
For more accurate results, instruments can be equipped with an automatic measurement range selection function. There are models in which this can be done manually.
Another important indicator is the display width, which is characterized by the ability to display a certain number of decimal places. Depending on this, devices can be with a bit depth from 2.5 (0.01) to 6.5 (0.000001).
It is important to know! It should be borne in mind that no matter what capacity the device has, the accuracy of all measurements will depend on the error rates of the tester.
Most testers are powered by 9 V crown batteries. This type of charge is suitable for occasional use of the device. If it is used for permanent work, then a li-ion battery should be preferred.
Helpful advice! If all measurements are constantly carried out on the same workplace, then it is advisable to power the device from the mains. For this you need a voltage converter from 220 to 9 V.
The peculiarity of the device operation is influenced by its electrical safety class. Multimeters class CAT I are designed to work in networks with low voltage. CAT II testers are used in household electrical networks. CAT III devices should be used in networks inside buildings and structures. And CAT IV measuring devices are intended for outdoor distribution works.
To measure the voltage in the home outlet, set the switch to the ACV position, install the black probe in the COM connector, and the red one – V? MA. If the estimated value is unknown, the measurement should be started from the maximum value – 750 V. If “0” appears, then go to a scale with a lower voltage level. For measuring DC voltage, for example, wiring in a car, set the switch to DCV mode.
To measure the current, it is first necessary to know which current is present in the circuit and its approximate value. It is important to select the appropriate connector for the red probe.
Helpful advice! In order not to cause the device to fail, without knowing the value of the current, you should insert a red probe into connector 10 A. If after the red probe is located in the socket 10 A, a small value is displayed on the display, then you should switch the plug to connector V? mA and set the required measurement range.
The most safe for the device is to measure the voltage. Is it enough to set the rotary switch to? and make measurements. It should be remembered that the power in the circuit must be turned off, otherwise the device will show the wrong value. If the display shows “0”, move the multimeter to a lower measuring range. If the display shows one of the values, “OL”, “1” or “OVER”, this indicates overloading of the device. In this case, you must set the switch to a higher range.
Using a multimeter, you can ring the electrical circuit. To do this, turn the switch to the required position and connect the red probe to the V? MA connector. In the case of a closed circuit, the tester will beep. It should be noted that the section of the circuit that is planned to be paged must be disconnected from the power supply.
When there is a question, which multimeter to choose for the house and the car, the choice is obvious. One of the best budget testers is a DT-830B instrument made in China. A small multimeter in size, it has a set of necessary functions that the home master will need.
It is suitable for measuring the voltage in the electrical network between two points, resistance, current values. With it, you can check the integrity of the semiconductor diode, determining its voltage, ring the electrical circuit at resistance up to 5 Ohm, test the semiconductor transistor, measure the inductance and capacitance. The best multimeter for home DT-830B can be bought for 250 rubles. The device has protection against loads, and the power is supplied from the 9 kr battery.
Many beginners have a question: how to use the DT 830B multimeter? Everything is very simple, the main thing is to follow the instructions to the device, which describes in detail all the steps necessary to measure a specific physical quantity. For example, for wiring wiring in an apartment or determining a break in the network, it is necessary to measure the resistance. To do this, the rotary switch is set to the appropriate position. If the device beeps, the circuit is closed. If there is no signal, this indicates a break in the circuit or the resistance value exceeds 50 ohms.
The device is characterized by high input resistance, which indicates the high accuracy of the device. The multimeter automatically determines the limit of measurement of physical quantities. The “hold” button allows you to fix the last value received. The tester is equipped with a system for automatically shutting down the device if it has been inactive for 40 minutes. Choose a digital multimeter, the price of which is about 1200 rubles., It is for professional use.
Select the measuring device on the basis of its area of further use. If the multimeter will be used exclusively for domestic purposes, then preference should be given to conventional models. For specialized measurements, purchase a multifunctional and highly accurate instrument.
