What is a voltage indicator, what are they and how to choose the right one

Even with the simplest work in electrical circuits on the farm, a voltage indicator is useful - a device that shows the presence or absence of electric current and voltage in networks from 220 to 1000 V (depending on the device). The expediency of its use is dictated primarily by the fact that the electric current cannot be seen with the eyes - its presence can be judged only by whether the device plugged into the outlet works or not.

Varieties of indicators

The main function that the voltage indicator should perform is to check the integrity of the electrical circuit - it depends on this whether the device plugged into the outlet will work or not. Different devices cope with this task in different ways - a standard screwdriver uses a voltage indicator to check the current that is already in the network (passive), and inside the multifunctional voltage tester there is a whole circuit with a separate power supply (active), which allows you to ring out even de-energized electrical circuits. All these devices work on a similar principle, but have some differences in the rules of use.

Passive screwdriver indicator

This is a single-pole household phase indicator that performs one and only task - to show the presence or absence of voltage at a certain point in the electrical circuit. It is not used by professional electricians due to its extremely limited functionality, but at home among the set of tools “just in case” it can come in handy.

The indisputable advantage of the device is that the single-pole indicator shows the presence of voltage after touching any current-carrying contact. The zero wire is not needed - its role is played by the human body, which is holding a screwdriver in its hands. The presence or absence of a phase is indicated by a neon lamp inside the device - to check the voltage, you need to touch the conductor with a screwdriver sting, and touch the contact plate on the handle with your hand.

To protect the user from high voltage, a resistor is installed between the tip and the lamp, but because of this, the indicator does not respond to voltages lower than 50-60 volts.

Active screwdriver indicator

A circuit is assembled inside the device body, powered by its own power source (batteries), therefore it is a more sensitive voltage detector. Instead of a neon lamp, an LED is used here, which reacts not only to touching the conductor, but also if the sting simply falls into the electromagnetic field that is around any energized conductor. This property is successfully used to find wiring in walls or where it breaks. You need to take a screwdriver by the sting and hold it along the wire - if in some place the lamp stops shining, then the wiring is damaged there (+/- 15 cm).

Also, the LED indicator will be triggered if you touch the tip with one hand and the contact plate in the handle with the other. This property is widely used for continuity of wires (determining their integrity). You just need to take one end of the wire in your hand, and touch the other with the sting of a screwdriver - if there is no break, then the indicator will light up.

The high sensitivity of the device is also its disadvantage - since the indicator can show the presence of voltage where it has never been, and vice versa - it will not react to a break in the neutral wire (except to change the phase and zero in places).

Multifunctional active screwdriver indicator

This voltage tester is an improved version of the previous tool - it features a switch that can adjust the sensitivity of the device, as well as use it in contact and non-contact modes.

Often, such a multifunctional indicator screwdriver is equipped with a mini liquid crystal display, which shows not only the presence of voltage, but also its voltage. This makes it possible to detect parasitic pickup currents that are difficult to recognize using a conventional voltage presence indicator.

In addition to the display, such devices are equipped with a buzzer, which allows using the device without interference in conditions when the digital indicator is not visible. In fact, the TOP models of electronic indicator screwdrivers are simplified multimeters, but with one sting instead of two probes. Some electronic indicator screwdrivers are even able to measure the temperature of the surface that the tip of the device touches.

Homemade probe (control)

An electrician's bag often contains a homemade voltage probe with an ordinary 220-volt light bulb - in professional jargon called "control". Despite its size, it is often more convenient, although all its advantages are fully revealed when checking three-phase networks.

In fact, this is an ordinary light bulb screwed into a socket, and the wires act as probes that touch the contacts on which you need to check for voltage. Compared with other simple indicator probes, the control does not just show the presence of an electric current - it is possible to understand from the brightness of its glow whether the voltage is normal in the circuit.

Additional benefits include the ability to check for all three phases. For example, if there are three wires and two of them are "planted" on the same phase, then any other voltage indicator at the other end of the wire will simply show that a phase comes to each core, and the electric motor will not start. In this case, two controls are taken, connected in series, and the phases are checked with free probes - on wires with one phase, the lamps will not light up. Plus, the control can always be used as additional lighting.

Of the minuses of the device, the only thing that stands out is that one phase can be checked only if there is a neutral wire nearby, although it is difficult to imagine a situation with its absence.

Universal probe

The most common voltage indicator among professional electrician tools, combining functionality and ease of use. A universal device that can do everything: it determines the phase and zero in the AC network, plus and minus when constant, rings the wiring, shows what voltage in the circuit, has audible and visual indication.

Not all such devices are able to find wiring through walls, but the rest of the functions are more than enough for the daily work faced by an electrician.

The measurement limits are determined by the quality of insulation and the model of the device - 220-380 or voltage indicators up to 1000 V and above.

Multimeter - all at once

Electrical universal tester, combining in one case all the main devices used by electricians and radio amateurs - a voltmeter, an ammeter and an ohmmeter. In addition, the device can test diodes and transistors, and measure the capacitance of capacitors.

The voltage indicator is characterized by high measurement accuracy - depending on the set mode, it determines the current strength, the resistance of the conductors and other values ​​up to hundredths and thousandths of units. It is equipped with a liquid crystal display for displaying measurement results.

Which is better to choose

All devices have their pros and cons that must be considered when buying them.In addition, you need to understand why it will be needed - for example, if the control has proven itself perfectly in three-phase circuits, then there is no particular point in making it for home use.

Oddly enough, but if a person does not understand electrics, then it is better for him to buy all the same a semi-professional device - at least a universal probe for 220-380v. In addition to the fact that this is just a reliable and necessary device, if you have to invite an electrician or ask friends to look at the wiring, then it is better if you have a good device at hand.