At the stage of assembly and subsequent servicing of any electrical devices, 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 checks of electrical circuits are performed, 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 to existing modifications. In addition, we provide a brief description of the ways of working. We remind you that
electric current is dangerous, therefore, without understanding your actions and their consequences, you can get an electric shock. Caution First! Imagine that an electric tester was purchased. 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.
What do electrical circuits check
The 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 indicator screwdrivers, specialized voltage indicators, as well as universal multimeters.
They differ from each other in their capabilities and cost. Which device to give preference to depends on the range of tasks and the qualifications of the employee.
Basic functions for little money
The simplest device that allows you to check the wiring diagram is an indicator screwdriver. The lower price bar of such a device is about 50 rubles. Outwardly, this device not only looks like a well-known tool for screwing out screws, but also copes with this task perfectly. However, there are differences. So, in the dielectric handle there is a transparent window, and on the side opposite to the tip there is a metal contact ring.
As you know, in an
electric circuit the greatest danger is a wire on which there is voltage - phase. A person touching him risks 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 necessary to check the conductors first. It is for solving this simplest task that the electric tester is designed - an indicator screwdriver. Work with it is carried out as follows: holding the device by the handle, with one finger you need to touch the upper ring, and touch the tested area with the probe. If a light is lit inside, then a phase is present on this conductor.
Advanced Screwdrivers
There are more complex modifications of the above device. Externally, these are two screwdrivers connected by a wire, on one of which there is a series of LEDs, each with its own designation - 12, 24, 110, 220, 380 V (the order and size in the models differ). The cost starts from 200 rubles.
How to use an electric tester of this class? The difference between such a complicated version of the screwdriver is the ability to evaluate the voltage value on each conductor, and not just to register the presence of a phase. To do this, one probe should touch one core of the wire, and the other - to the "ground". If a number of diodes are lit, the latter will indicate the magnitude of the EMF present on the tested conductor. If not, then this means that the phase on the vein is absent. Touching two wires with different phases will cause a “380 V” glow. Note that in the case of the same phases, the diodes will remain dark, and this also needs to be taken into account.
Contact tester electric
This group of devices in its capabilities significantly exceeds the above-described "screwdrivers". Although the correct name sounds like a "Voltage Index", when buying or searching for information about them, it is quite possible to come across the term "tester". In principle, this is true. For electricians at large enterprises and in electric grid services, voltage indicators for 0.4 kV are issued as the main tool. And it is right. The electric tester "multimeter", which performs the same tasks as the pointer, significantly loses to the latter in terms of ease of use and reliability. We will describe the class of multimeters a little lower.
Phase detection mode
Externally, the voltage indicator resembles a complicated indicator screwdriver: the same two probes, the same row of LEDs, even a connecting wire.
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 the rest of the signaling devices, and separately - from the side opposite to the probes.
The Ph electrode and its LED are for the phase wire detection mode. How to use an electric tester of this design? Here is the algorithm for checking the voltage on the conductors:
- the auxiliary unit (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 your hand with him aside;
- Touch the Ph electrode with your finger. It is absolutely safe. You need to understand that in this case the human body is used as a capacitor, so the hand should not be covered with any dielectric material;
- holding your finger on Ph, touch the main unit with the probe of the main unit. If the corresponding LED lights up, then there is a phase on this conductor. 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 use the auxiliary unit, but not the main unit, to check the phase conductor, touching the probe with its probe. However, this is not recommended, since if the wire connecting the blocks is damaged (for example, inside the insulation), the indication will simply not work. And the error in determining the phase wire is a direct danger to life.
Determine the effective voltage
This device allows you to find out what voltage is present on the tested conductor through a few simple steps.
The procedure for using the pointer in the EMF value determination mode is completely identical to that in the case of a complicated indicator screwdriver.
Circuit integrity
The restoration of electrical circuits is impossible without checking the areas for damage that impede the passage of current through them. The voltage indicator of the type “Contact” in its capabilities resembles a universal electric tester, as it is capable of performing such a test as the last one. To do this, a capacitor is installed inside the device, which must be charged before starting work by touching the probes on a "phase-zero" or "phase-phase" for 6-10 seconds. After that, it becomes 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 the outgoing lines turned off), you need to touch the first probe of the tester to one terminal of the heater, and the second to the other. If the coil is whole, the Test diode will light up. Touching the output and the housing, you can check the heating element for the presence of "breakdown", etc.
All in one
But the most versatile device is a multifunctional electric tester. It can be compared with a folding travel knife, which has everything you need. What is an electric tester?
The photo shows that on this device there is a circular switch, rotating which you can select the desired mode of operation. It is important to read the notation very carefully, since due to the haste in the measurements, a lot of such devices burn out. Given the number of measurements taken and their limits, this particular tool is sold at the corresponding 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 former 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, dial multimeters are significantly less digital. In the latter, instead of a scoreboard with an arrow, the simplest microprocessor is used, which displays the result on a small display. However, no additional recounts are required. In most cases, you need to purchase a device with such a universal system. There are combined models that have both an arrow and a display, but they cost more.
Compared with indicator screwdrivers and voltage indicators , universal testers allow you to measure the resistance value, check the transitions in the semiconductors of transistors, the current value of the current, and determine the “punched” diodes. In addition, depending on the modification, digital testers allow you to check the ambient temperature using the built-in or additional sensors, the frequency of the electrical circuit, as well as the capacitance of the capacitors.
How to check the integrity of the circuit with a multimeter
In solutions of the initial price category on the case there are three holes to which wires with probes are connected. One connector is necessarily designated as COM - it is used in all cases. To the second, next to which “V, mA, Ohm” (or an English analogue) is indicated, a wire is connected if it is necessary to measure small current (in milliamperes), voltage and resistance. But the third socket is used if it is necessary to determine a high current load (usually it is up to 10A, a constant type of current).
Integrity test is similar to resistance measurement, with the only difference being that the switch should be turned with a pointer to the item with the corresponding image (for example, a speaker). One wire with a probe must be connected to the COM connector, and the second to the above jack. 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 site. If “0” lights up on the display and a sound is heard, the circuit is intact. Of course, it is recommended to disconnect all other lines from the element being checked and, without fail, to de-energize it.
How to check battery voltage
The possibility of determining 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 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 simultaneously touch the poles of the battery. The measured value will be displayed on the screen.
Of course, in this article we cannot cover all the options for using the tester. For 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 the circuit break. Having turned off the power supply to the circuit, it is necessary to fix the first probe on one side of the section being tested, and the second on the other. After switching on, current will flow through the device, which will display it on the display. For high values, use connector “A”. And again, to avoid electrical injury and protect the device from damage, you need to read the instructions.