When a malfunction occurs in the electrical wiring is not always appropriate to call a specialist, because the cause can be quite simple. Some breakdowns can be repaired yourself by using such a device as an indicator screwdriver. Useful in everyday life, the device is reliable and easy to handle, capable of replacing expensive and complex tools. You do not need to be an electrician to check electricity, with a minimum knowledge of electricity you can use the screwdriver to determine the "phase" and "zero" wires.
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How an indicator screwdriver works
Universal, affordable for any consumer, the indicator screwdriver is designed to detect the presence or absence of alternating voltage. Its main difference from a regular screwdriver is the presence of a built-in indicator element in the handle cavity. The tip of the probe (stylus) serves as a kind of conductor (contact part). Simple models are equipped with neon lights.
The principle of operation of a standard indicator screwdriver is based on current flowing through the tip (stylus) and resistor to the contact of a neon or LED light bulb, which causes it to light up. If the device fails it is necessary to replace the batteries or the tester itself (in case it is broken).
How does the universal indicator screwdriver work?
An important condition for the operation of the tester is the closure of the second contact, which is located on the handle. To do this, it is necessary to touch the end part of the device (the heel) with your finger (the body of the wizard serves as a circuit element). Thanks to the built-in resistor, the amount of current flowing through the tool is safe for the user.
A functional screwdriver, also called a voltage indicator, consists of several uncomplicated parts. The construction of a standard indicator screwdriver is as follows:
- A plastic frame (handle body);
- The metal "stinger";
- Conductive contact and limiting resistor built into the housing;
- spring;
- Neon or LED indicator;
- contact plate.
Types of Indicator Screwdrivers and their Features
Modern indicator screwdrivers are divided according to the type of design and principle of operation. Thanks to a wide range of devices, users can choose a reliable and functional tool depending on financial capabilities, personal preferences (for home or professional use).
Types of indicator screwdrivers popular among users:
Standard device with a neon light element - A simple device of the contact type. The light bulb built into the tester begins to glow when current flows through the tip of the screwdriver and a resistance resistor. The circuit is closed by pressing the "heel" (the contact plate on the end of the handle) with your finger. A glow indicates the presence of a phase on the power source being tested (wire, switch, socket or other electrical appliance). The disadvantage of this model is considered a rather high indication threshold - the device does not function at voltages below 60V. An ordinary indicator-type screwdriver works without the use of batteries, designed only to identify phase-zero, breaks in the circuit with its help can not be detected.
Devices with an LED light element are similar in principle to a model with a neon bulb, but have a lower indication threshold (less than 60V). The tester works from a self-contained power source (batteries). With a multifunctional device equipped with a bipolar transistor, you can:
- determine phases;
- detect line breaks and contact faults;
- determine the polarity of various DC sources;
- identify the location of the cable in the wall (under the plaster) by non-contact method;
- check the integrity of fuses and conductors.
Electronic device with liquid crystal or simple display often used as a mini multimeter. The universal indicator screwdriver has a buzzer and compact size. On the handle of the electronic device are:
- display;
- function buttons;
- voltage indicator pointer;
- marking from the manufacturer.
Improved models are equipped with an inductive probe (stinger). For consumers who do not know how to use the screwdriver indicator with LCD display there are special instructions for use.
The electronic tester has the following applications:
- determination of voltage levels;
- testing for the integrity of various conductors, power lines, power networks;
- identification of "earth/phase";
- polarity check;
- detecting electromagnetic and microwave radiation.
In addition to the above functions, this screwdriver-indicator is successfully used as a search detector, which allows you to detect hidden wiring. The model with LCD display is characterized by its multi-functionality and high cost.
Ways to use
The standard system of domestic houses is a single-phase network with two wires "zero" and "phase". To make repairs on electrical wiring must identify the correct wire, for this voltage tester is inserted into a socket or touch it to the investigated conductor. The presence of a glow in the tester reveals "phase", the absence - "zero".
To check the integrity of light bulbs, it is best to use a screwdriver-indicator with an LED. To do this, holding the bulb by its base, you must put the stylus (stinger) of the tool to its center contact. The finger touches the contact plate on the handle (heel). A light or sound signal indicates the operability of the illuminator.
In the same way the integrity of the wire is checked, one end of which (stripped) is taken in one hand, and the other end is touched with the tip (stylus) of the screwdriver. The glow signals the integrity of the wire, the lack of reaction - the break of the contact. At the same time there should be no voltage in the tested conductor.
Electronic devices do not require a person to touch the plate on the handle. To detect the presence of voltage, it is enough to touch the test object with the stylus of the tester.
The working condition of the extension cord is checked as follows:
- the device is disconnected from the electrical equipment and network;
- insert into his socket any wire with stripped ends (contacts should be shorted);
- clamp in his hand one of the contacts and the plug, and the other touch the voltage indicator;
- if the extension cord circuit is functioning properly, the light bulb begins to illuminate. Before you plug in the equipment, remove the jumper to prevent a short in the wiring.
If the indicator does not respond, you should connect the extension cord to the mains and slowly run the tip of the handle (the nickel) of the tester along the entire length of the RCD (the screwdriver is taken by the stylus). In the places of damage, the intensity of indication is reduced or there is no glow at all. To restore the working condition of the extension cord in the detected places of breakage the insulation is removed, the damage is found, the wires are twisted and insulated. The best option is to buy a new electrical device.
The location of hidden wiring is determined by running the back side of the tester along the wall, holding it by the probe (stinger). An increase in the intensity of the glow or the presence of a sound signal indicates the presence of conductive wiring behind the plaster. This method is not considered accurate enough, and in panel buildings is not appropriate.
How to use an indicator screwdriver
When working with the electrical grid, you need to follow safety rules and know how to use the tester-indicator. The main point is to disconnect package breakers in electrical circuits when disassembling switches, outlets, etc. You should also make sure that the device is working, because the accuracy of the readings and the safety of the user (master) depends on its technical condition. The instrument must have a whole body - without chips, cracks, and so on. If there is minimal damage, the device is replaced, since the consequences of an electric shock can be irreversible.
The working condition of the tester is checked by shorting the circuit by hand (putting your fingers on the probe and the "heel" of the tester at the same time). Lack of luminescence occurs in two cases:
- When the instrument fails and must be replaced. Repair is not advisable, because the effort required will be much more than the cost of a new instrument.
- When the batteries are dead and need to be replaced with new ones. When installing them, pay attention to the polarity, otherwise the device will not function.
How to choose an indicator screwdriver
Before you choose a suitable indicator screwdriver, you should decide what you need it for - for what kind of work (for home use or professional). Budget variants are not inferior in quality to more expensive analogues, but are distinguished by a narrow set of functions. Indicator devices are sold in retail outlets, specialized departments and online stores. The cost of the testers varies between 50 and 1500 rubles, depending on the technical characteristics, modification and manufacturer. Before choosing the right screwdriver-indicator, it is advisable to read the reviews and descriptions on the Internet. The following features are indicative of the high quality of the tool:
- durable stainless steel rod;
- a handle with a reliable dielectric surface;
- intact, undamaged handle.
The scope of application of this device is wide, which makes the practical, easy-to-use device an invaluable aid in uncomplicated electrical work. With all the useful indicating properties, the tool does not cease to be a screwdriver, so some users use it when screwing fasteners.
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