At the stage of assembly and subsequent maintenance of any electrical appliances, it is impossible to do without special tools. Among them, one of the most popular is an electric tester. It is with its help that electrical circuits are checked, as well as their restoration, if necessary.
But if for a specialist familiar with electrical engineering, the task of choosing this device is easily solved, then for an unprepared person this is a whole problem. In this article, we will explain in a simple accessible language how to choose an electric tester, and also point out existing modifications. In addition, we give a brief description of how it works. We remind you that electric current is dangerous, therefore, without understanding your actions and their consequences, you can get an electrical injury. Caution first! Let's imagine that an electric tester is bought. The instruction is always attached to it, and it is necessary not only to read it, but also to understand what caused the requirements indicated in it.
Term"electric tester" is used in relation to a device that checks electrical circuits. There are several varieties of these devices, among which the most famous are indicator screwdrivers, specialized voltage meters, and universal multimeters. They differ from each other in their capabilities and cost. Which device to give preference to depends on the range of tasks to be solved and the qualifications of the employee.
Basic features for little money
As you know, in an electrical circuit, the greatest danger is the wire on which there is voltage - the phase. A person who touches it risks getting an electric shock. Moreover, it does not matter which phase is on the conductor (A, B or C). But the neutral wire and the "ground" are safe. Therefore, when performing work in electrical circuits, it is imperative to first check the conductors. It is for the solution of this simplest task that the electric tester is intended - an indicator screwdriver. Working with it is carried out as follows: holdingdevice by the handle, with one finger you need to touch the upper ring, and with the probe touch the area to be checked. If a light is lit inside, then there is a phase on this conductor.
There are more complex modifications of the above device. Outwardly, these are two screwdrivers connected by a wire, one of which has a row of LEDs, each with its own designation - 12, 24, 110, 220, 380 V (the order and size differ in the models). The cost starts from 200 rubles.
How to use this class of electric tester? The difference of such a complicated version of a screwdriver lies in the ability to estimate the magnitude of the voltage on each conductor, and not just register the presence of a phase. To do this, you need to touch one core of the wire with one probe, and with the other - to the "ground". If a number of diodes light up, then the latter will indicate the magnitude of the EMF present on the conductor under test. If not, then this means that the phase on the core is missing. Touching two wires with different phases will cause "380V" to glow. Note that in the case of the same phases, the diodes will remain dark, and this must also be taken into account.
Electric tester type "Contact"
This group of devices is much superior in its capabilities to the above-described "screwdrivers". Although the correct name sounds like "Voltage Gauge", when buying or searching for information about them, it is quite possible to come across the term "tester". In principle, this is true. Electricians onin large enterprises and in power grid services, voltage indicators for 0.4 kV are issued as the main tool. And it is right. An electric "multimeter" tester, which performs the same tasks as a pointer, is significantly inferior to the latter in terms of ease of use and reliability. We will describe the class of multimeters below.
Phase detection mode
The difference is that on the main unit there is a metal Ph electrode recessed into the body - a thin metal pin, as well as an LED with the same designation. Depending on the design, the latter can be placed both together with other signaling devices, and separately - on the side opposite to the probes.
The Ph electrode and its LED are designed for the phase wire detection mode. How to use an electric tester of this design? Here is an algorithm for checking the voltage on the conductors:
- the auxiliary block (there is no indication on it) must be taken in such a way as to exclude the possibility of touching the probe metal with your hand. Usually it is enough just to take the hand with him to the side;
- touch the Ph electrode with your finger. It's absolutely safe. It must be understood that in this case the human body is used as a capacitor, so the hand should not be covered with any dielectric material;
- holding a fingeron Ph, touch the test area with the probe of the main unit. If the corresponding LED lights up, then there is a phase on this conductor. The light indication may be accompanied by sound and be intermittent - it depends on the model. If the LEDs are dark, then this is "ground", "zero" or a temporarily de-energized area.
It is allowed to check the phase wire not to use the main unit, but the auxiliary one, touching the core with its probe. However, this is not recommended, because if the wire connecting the blocks is damaged (for example, inside the insulation), then the indication simply will not work. And an error in determining the phase wire is a direct danger to life.
Determine the effective voltage value
The procedure for using the pointer in the mode for determining the EMF value is completely identical to that in the case of a complicated indicator screwdriver.
Chain integrity
Restoration of electrical circuits is impossible without checking the sections for damage that prevents the passage of current through them. The voltage indicator of the “Contact” type is similar in its capabilities to a universal electrical tester, as it is capable of performing such a test as the latter. To do this, a capacitor is installed inside the device, which must be charged before starting work by touching the probes on the "phase-zero" or "phase-phase" for 6-10 seconds. AfterThis makes it possible to check the circuit for integrity. For example, there is a heating element that does not heat up. In a de-energized state (with disconnected outgoing lines), you need to touch the first probe of the tester to one output of the heating element, and the second to the other. If the spiral is intact, then the Test diode will light up. By touching the terminal and case, you can check the heating element for "breakdown", etc.
All in one
The photo shows that this device has a circular switch, by rotating which you can select the desired mode of operation. At the same time, it is important to read the designations very carefully, since many such devices burn out due to haste in measurements. Given the number of measurements and their limits, it is this tool that is sold at the relevant points of sale as an “electric car tester”. The cost of these devices starts from 250 rubles.
Multimeters come in two subspecies - analog and digital. The first ones are equipped with a classic electromagnetic deflection system, and there is a pointing arrow in their design. In many cases, this solution allows for more accurate measurements, however, due to the need to recalculate the scale in terms of convenience, pointer multimeters lose significantly to digital ones. In the latter, instead of a scoreboard withthe arrow uses the simplest microprocessor, which displays the result on a small display. In this case, no additional recalculations are required. In most cases, you need to purchase a device with just such a universal system. There are combined models that have both a hand and a display, but they are more expensive.
Compared to indicator screwdrivers and voltage indicators, universal testers allow you to measure the resistance value, check transitions in transistor semiconductors, the effective current value, and determine “broken” diodes. In addition, depending on the modification, digital testers allow you to check the ambient temperature using built-in or additional sensors, the frequency of the electrical circuit, as well as the capacitance of capacitors.
How to check the circuit for continuity with a multimeter
In the solutions of the initial price category, there are three holes on the case to which wires with probes are connected. One connector is necessarily marked as COM - it is used in all cases. To the second, next to which is indicated “V, mA, Ohm” (or the English equivalent), a wire is connected if you need to measure a small current (in milliamps), voltage and resistance. But the third socket is used if it is necessary to determine a high current load (usually up to 10A, a constant current type).
Checking for integrity is similar to measuring resistance, with the only difference being that the switch should be turned to point to the item with the corresponding image (for example, speaker). Onethe wire with the probe must be connected to the COM connector, and the second one to the above socket. By touching the first probe to the beginning of the line being checked, and the second to the end, you can check the integrity of the section. If “0” lights up on the display and a sound is heard, then the circuit is intact. Of course, it is recommended to disconnect all other lines from the element under test and, of course, de-energize it.
How to check battery voltage
The possibility of determining the potential is no less in demand. For example, the owner of a multimeter needs to check the voltage on the battery. To do this, one probe is connected to the COM, and the second - to the "V" connector. The switch is placed in the DCV position with a value of 20 V. After that, it remains to touch the battery poles at the same time. The measured value will be displayed on the screen.
Of course, in this article we cannot cover all the options for using the tester. To do this, the owner is advised to carefully read the instructions and follow them.
How to measure current
All budget multimeters allow you to determine the current consumed by the load. For such measurements, the device is connected to a break in the circuit. Having turned off the power supply to the circuit, you need to fix the first probe on one side of the area to be checked, and the second on the other. After switching on, the current will flow through the device, which will display it on the display. For high values, connector "A" must be used. And again, to avoid electrical shock and protect the device from damage, you need to read the instructions.
