You've probably seen a voltage indicator in the shape of a pen more than once. It is convenient to carry it in the breast pocket of a shirt or overalls. Some modern models Such indicators can detect voltage even without metal contact with a live conductor. This species electrical protective equipment and this is what our article is dedicated to.
Terminology
In numerous articles posted on the Internet, you can find the terms “voltage indicator”, “indicator low voltage", "voltage indicator". However, often no distinction is made between the areas of their use, and sometimes they are even identified. Let's try to understand this issue.
A palm-sized 4-volt cordless screwdriver with a gyro sensor that detects a wrist snap, then sends the bit spinning. Anyone who lives in a house full of screws that sometimes need to be loosened or tightened. The gyro sensor becomes intuitive once you get used to its behavior.
When the bit is clamped into the head of the screw, turning your wrist in a counterclockwise direction will begin to unscrew the screw, or vice versa. The heel of your hand suppresses the large button, but your index finger does not grip the trigger. To stop it, you either turn in the opposite direction or take your hand off the button.
Numerous rules for the use of electrical protective equipment, which are constantly changing and republished, always use the term “voltage indicator”. In this case, all such devices are divided into bipolar ones, consisting of two bodies connected by a flexible insulated conductor; and single-pole, containing one body. The first ones work for active current, flowing through both housings, and the second - on capacitive flowing through the user's body.
This is great for tightening and loosening screws in finished furniture, door hinges and box hardware. The specifications claim that the battery will charge for "18 months." But there's no battery life indicator on the tool, and you can't tell when it's reached full charge when plugged in.
The gyroscope will not be considered in the hands of many contractors on construction sites. But if you know someone who is looking to pick up a power tool for the first time, this great place for starters. It's amazing to think how much I've grown over the last ten years. Ten years ago no one else took Milwaukee seriously, now they're all playing catch up. Milwaukee leads the way in new innovations and new products month after month. A couple of years ago they didn't even have hand tools. Now their cast is numerous and a force to deal with.
The widely used term “voltage indicator” refers specifically to the second type of indicator. Their early models were produced in the form of a screwdriver with an indicator light in the handle. Modern devices more like a construction marker (though with a metal contact part at the end).
A few words about the containers around us
How does a capacitive voltage indicator work? To understand this, let's go back for a moment to electrical theory circuits and remember how a capacitor functions. It has two conductors, or plates, separated by a dielectric. Many people think that capacitors are separate elements of electronic circuits, but in reality the world is filled with capacitors whose presence we usually simply do not notice. Here's an example. Suppose you are standing on a carpet covering a concrete floor directly under a 220-volt light fixture. Although you may not feel it, your body is conducting very little (on the order of a microampere) alternating current because it is part of a circuit consisting of two series connected capacitors. The two plates of the first capacitor are the filament in the light bulb and your body. The dielectric is the air (and maybe your hat) between them. The plates of the second capacitor are your body and the concrete floor (it is a fairly good conductor).
Speaking of new hand tools, let's move on to the Milwaukee Screwdriver review. Milwaukee uses a three-blade handle, which means greater comfort and best way shoulder applications. End caps are designed to withstand abuse, such as hitting with a hammer. They are made of high strength steel. The end caps also have a visual indicator so you know which screwdriver you're grabbing from your belt or bag.
High impact steel shanks do not stop at the beginning of the handle. In fact, the shaft runs through the handle and sits directly under the end cap for maximum impact energy transfer. The shaft also has hexagonal shape so you can use it with wrench.
The dielectric of the second capacitor is the carpet plus your shoes and socks. Since the concrete floor is well grounded, so is neutral wire supply network, a voltage of 220 V is applied to the circuit of these two series capacitors. 
Where is the voltage indicator?
Understanding how grid voltage is divided between two series capacitors, is critical to figuring out how a capacitive indicator works.
Milwaukee screwdriver
Now we didn't work with them. They're comfortable, and while we don't hit them, they feel durable and a tool you can abuse over and over again. Let's be honest, it's difficult to test and report the performance of a screwdriver. The bottom line is the comfort and quality that these screwdrivers bring to the table.
Milwaukee Screwdriver Final Thoughts
The screwdrivers are quality and should last a long time, even with heavy use. Milwaukee has added another great product to their tool line. If you are looking for screwdrivers that you can use in your demo work, these are something to consider when next purchase.
Let's return to the theory of electrical circuits. IN series circuit the voltage will be distributed according to the resistance value (Ohm's law). For a capacitor, the smaller its capacitance, the greater the so-called capacitive resistance to alternating current. Thus, when two capacitors are connected in series, the largest fraction of the voltage applied to them will be dropped across the smaller device.
Types of indicator screwdrivers
Screwdriver for dry walls. Removable depth of field indicator. Speed adjustment. Housing for gears and metal diaphragm. The handle has a comfortable feel and a two-finger trigger. Fast and silent drive coupling. Steel gears. Heat treated for durability.
In this guide, we explain how to choose your search stage by evaluating the features and prices of commercially available products. A phase detector is a special type of screwdriver capable of detecting the presence of electrical voltage on any element of the circuit. By inserting the part, the phase-scanning screwdriver detects the presence of a phase on the conductor. This particular tool comes with a clear and insulating handle that has a small neon light inside with electrical resistance, connected in series with its rod, and on the opposite side it is connected to a plate located above the handle.
In the example above, only a few volts are between your feet and the floor (at the larger capacitance), and the rest of the 220V is applied between your head and the light bulb filament (at the smaller capacitance). Now if you keep thumb on the contact pad at the end of the capacitive indicator handle and touch it to the bare section of the wire powering the lamp, then instead of a small capacitance, a voltage indicator circuit sensitive to low currents is included in the capacitive current flow circuit. This current, of course, increases, but a high-resistance resistor inside the indicator limits it to a non-hazardous value. As a result of the flow of current, a neon lamp or LED lights up in the indicator or a buzzer sounds.
To use this tool, simply keep your finger in contact with the roller and press down on the parts you want to control. If voltage is present, the light comes on. Monitoring the presence of voltage is extremely important when new circuits or derivatives of existing ones are manufactured, since relevant regulations require differentiating phase conductors from neutral and ground conductors.
Universal indicator screwdriver
As if this were not enough, searching for the presence of a phase makes it easier to detect any fault. As it turns out, the screwdriver needs to be used with a tact to make sure it doesn't damage it, as accidental impacts can cause injury to the spy and drag, effectively preventing the tool from searching for answers.
Traditional capacitive indicator
Mains voltage indicators in the form of a screwdriver, showing which pin of the electrical outlet is in phase and which is in zero, appeared back in the 60s of the last century. Their electrical circuit includes a series-connected metal probe-tip, a high-resistance resistor in the resistance range from 0.47 to 1 MOhm with a small intrinsic capacitance between its terminals (for example, type MLT-1.0, VS-0.5, MLT-2.0 ), a neon light and a contact pad at the end of the handle. When the tip of a screwdriver touches the “phase” conductor and the capacitive current circuit is closed through the contact pad and the user’s body, the neon lamp lights up, which is a sign of voltage in the operating range of the indicator from 90 to 380 V (sometimes from 70 to 1000 V) at a current frequency of 50 Hz .
The principle that governs the operation of a screwdriver is very simple, by touching a tool with a live conductor, the current enters the stem, crosses the resistance, causes the light bulb to light up, crosses the hand, which makes contact with the outer contact then lands on the ground. It turns out that the light comes on, indicating the presence of voltage. The person performing the operation is free from risk and does not even notice the passage of current, since the resistance inside the screwdriver is so great that it carries less than one milliampere of current, an amount of current that is not perceived by the human body.
Why neon light bulb?
Can it be replaced with another indicator? For a long time it was thought not. Indeed, with capacity human body of the order of hundreds of pF and a voltage of U = 220 V, the maximum capacitive current with a frequency of f = 50 Hz through it to ground is U/(1/ωC) = U2πfC = 220 x 6.28 x 50 x n100 pF = n7 μA. And for an LED to light up, a current of the order of milliamps must pass through it. However, special circuit solutions were found that made it possible to create a voltage indicator using LEDs, piezoceramic buzzers and other indication elements.
Phase Features
At the beginning of this guide, we briefly looked at how a septic screwdriver is made. So, let's dive into the details to better understand the composition of this tool. These tools are for sale different sizes and can be used, if necessary, as a screwdriver. Compared with traditional ones, they have a certain difference, the structure is composed of an insulated stem, except for the end part, which penetrates into the transparent and insulating handle. In contact with the barrel we find a very high resistance and then a neon light bulb.
From neon to LED
The solution was to change the glow mode itself from continuous to pulsed. If you try to estimate the power consumed by a neon lamp, then at a voltage of 100 V and a capacitive current of 20 μA, it will be 100 x 20 μA = 2 mW. If you supply such power to the LED over a time interval, for example, 10 ms, and not a whole second, then it will light up quite well during this interval. After all, at a voltage of 100 V, the current through it will be 0.002 W x 100/100 V = 0.002 A = 2 mA.
Why neon light bulb?
The assembly contains a coil spring that, on the opposite side, contacts a metal plate that extends inside the rear of the handle. This has several applications, let's find them together in detail. Testing the Socket A sealed screwdriver can be used to test for the presence or absence of current inside the socket, or to determine if a phase cable is present. In this case, you will need to disconnect the dish and avoid tension while touching the clamp.
Determination of indication voltage
Insulated Carcasses The phase screwdriver also allows us to check whether the device is properly insulated from voltage. If it is on the frame, it will indicate that there is an internal contact and that the ground is faulty. In this case, you need to unscrew the lamp and touch the center contact or threaded ring with a tip.
If you ensure the accumulation of energy in some circuit (for example, in a relaxation generator) for a fraction of a second, and then sharply release it to the LED in 10 ms, then the latter will periodically flash brightly. It will work out LED indicator voltage without built-in battery.
After turning on the switch, you can also check its functionality. The search phase usually has low price, you can find models suitable for the needs of most people under 5 euros. Professional devices can exceed 20 euros. Bestseller Bestseller No. 6 Bestseller No. 6.
Electric torches prevent potential shock when working in dark environments. Indicates low battery: The indicator indicates that you can replace the battery in time. Selling Top Sellers No. 9 Top Sellers No. 9. Accurate measurement - provides convenient and convenient way checking electrical lines. The audible and visual alarm always contains a low voltage indicator. The low voltage indicator can remind you to replace the battery in time. Automatic setup sensitivity makes the test simple. . Continue traveling around the Czech Republic and Europe.
Which way did they go in China?
Chinese developers decided that since an LED requires a constant current of the order of several milliamps to glow continuously, they need to build a AA battery (or two) into the indicator. In this case, the current through the LED opens the simplest transistor switch, driven by capacitive current through the user's body.
It's still good old navigation, but it's still good, and it's always safe to keep track of saved and updated maps. An interesting error occurred recently. I finally fixed the navigation. The first was the loss of capacity of the built-in battery, which is actually not a bug, but wear and tear.
Replace the battery while in navigation mode. The first is a touch change on the display for multiple crowns, but this is a little more difficult to replace. Let's start by unscrewing the two screws in the top corners of the rear plastic. In the left top corner The screw is located on the rubber cover of the external antenna connector, also select here, it is just inserted.
Has the scheme been simplified? In general, yes, but she became extremely sensitive to various kinds tips. Therefore, the reliability of the readings of such indicators is questionable.
Digital voltage indicator
The glow of a neon light bulb or LED, of course, reliable way indication of the presence of voltage, but it is too uninformative if the circuit has several voltage levels. In this case, measuring electronics, which has rapidly developed in recent decades, comes to the rescue.
Safety precautions when using indicator screwdrivers
When the bolts are removed, the inside is left free of the black packaging, with plastic tabs in the grooves on the opposite side. Use and carefully fold along the edges and along the edges, pressing the black plastic outward. When the plastic tabs are released we distract inner part navigation panel from the packaging.
You can then easily move the interior of the navigation system from the bottom of the cover. First, pull the small power connector to the left, then release the conductive tape on both sides with a thin screwdriver, which can be easily pulled out. The figure shows two navigation sections.
The most in a simple way To make the indicator more informative is to introduce several voltage comparators into its circuit, which operate at different voltage levels. The output of each comparator controls its own indication element on the device body.
A real digital voltage indicator is obtained if the measured voltage is digitized on the built-in ADC, and then, through a special circuit, is supplied to seven-segment display elements capable of displaying numbers from 0 to 9, or to a small-sized matrix digital indicator. Expensive professional voltage indicators are built using this scheme.
Where is the voltage indicator?
Using your hand, gently pull the plastic up and with your other hand, try to push the tabs through the screwdriver, pressing the tabs into the hole, pushing the display out of the frame. For safer navigation, it is recommended to use soft panel, such as the blister foil in which the new display was packaged.
To the left of the frame is a new display, broken on the right. There is a black frame on the bottom. All that remains is to combine both halves into a functional unit. First, we check that the plastic elastic wire guards are deflected in order to insert the cable into the connector. To use them we use a narrow screwdriver.
You need to be on top of things with electricity!!! (time-tested wisdom).
Many have probably heard that a real electrician is not one who is not afraid of electricity, but one who is able to avoid direct contact with electricity. According to statistics, from defeat electric shock, electricians with ten or more years of experience most often die. It is at this age that the sense of danger becomes dull. Some experienced electricians check the presence of electricity by touch, yes, by touch. But why risk your own life when there are instruments that indicate the presence of voltage?
We have installed reverse side navigation, check the open wide connector. Bye navigation system is in two halves, just connected by wires, we can turn it on and check its functionality. After software ends, touch should also work.
Then connect the bottom navigation, frame and cover and then click on the top projections. When everything fits together well, tighten both screws and lock rubber cover external antenna.
We installed the reverse side of the navigation, check the open wide connector. While the navigation system is in two halves just connected by wires, we can turn it on and check its functionality. After the software finishes, touch should also work.
There are quite a lot of devices that indicate the presence of voltage - from the simplest voltage indicator on a gas-discharge light bulb (neon) to devices that show not only the presence of voltage but also many other parameters.
In this article we will look at indicators and voltage indicators which are most often used in their practice, such as professional electricians, and home craftsmen. In electrical installations, indicators with signal lamps are most often used.
Relatively recently, we have had voltage indicators that allow us to detect the presence of voltage without direct contact with a live conductor.
Example of this type The devices are equipped with a Chinese-made indicator (even though it says everywhere that it was made in Germany) - MS-18, MS-58, etc.
Such indicators consist of an LED, two miniature batteries and a pair of radio components. Such indicators can be used safely if you have enough experience and knowledge in electricity, since these indicators react to everything. For novice electricians and people without experience, using these probes is undesirable and even dangerous.
Two-pole voltage indicator consists of a neon lamp, additional resistance and contacts 1. Neon lamp, so that there is no glow under the influence of capacitive current. The indicator elements are fixed in two plastic housings 2, connected flexible wire 3 1 m long with increased reliability insulation.
Bipolar indicators require touching two points of the electrical installation, between which it is necessary to determine the presence or absence of voltage.
There are quite a lot of varieties of such indicators. They also differ in functionality.
The simplest indicators only show the presence of voltage. An example of such an indicator is the PIN-90 series devices (-2m, -2mu), UN500, -453, UNNU-1, UNN-10, MIN-1, etc. More advanced models - the ELIN-1 series (-SZ, -S3 IPM, -S3 Combi) and many other devices show not only the presence of voltage in the test section of the circuit, but also its nominal value and voltage polarity.
The following indicators are used: neon lights, LEDs various colors, digital and indicators. There are also combined indicators, where along with light indication there is also sound, which makes working with devices more comfortable and safe.
Unlike single-pole pointers and indicators, in order to find out about the presence of voltage with these (double-pole) devices, it is necessary to use two probes. The use of such devices gives a more complete picture of the presence or absence of voltage, which is undoubtedly very important in the work of electricians.
In addition to checking for the presence or absence of voltage in the section of the circuit being tested, some bipolar indicators can be used as a “continuity test”, that is, to check the circuit for an open circuit.
Digital devices are also quite popular among electricians. These universal devices allow you to check voltage, resistance, etc. The display uses a digital display, sound and light indication.
Some models are equipped without disturbing the conductor insulation. Also, many tester models are equipped with a temperature sensor, with which you can measure the temperature of equipment - transformers, motors, power switches.
Cautions:
1. It is not permitted to use a test lamp (a regular socket with two terminals) as a voltage indicator in networks with a line voltage greater than 220 V, since if it is switched on by mistake, line voltage in a 380/220 V network, the lamp explodes and fragments can injure the worker.
2. In practice, single-pole voltage indicators are often made on their own, usually in the form of a screwdriver. In this case, there are cases of improper manufacturing, and then there is a danger of electric shock. You cannot make the screwdriver shaft longer than 20 mm. If the rod is long, there is a danger of touching it when checking the voltage. It is advisable to tightly pull the insulating tube onto the rod, leaving an uninsulated section of no more than 5 mm in length. On the side close to the voltage source, there must be a thrust ring protruding 3-4 mm to prevent the hand from slipping.
Particular attention should be paid to the selection of a neon bulb so that the ignition threshold does not exceed 90 V. The IN-3 type lamp is most suitable. The additional resistance must be at least 200 kOhm.
The housing should be made of hard rubber or plastic of a dark color, in which it is easier to notice the glow of the light bulb. Manufactured signs must be tested.
In any case, using indicators and voltage indicators, knowledge and skills are required when working with them. Also, do not forget about safety precautions. And, trust the professionals, electricity, as you know, does not forgive jokes and mistakes!