How the indicator screwdriver works
Indicator screwdriver (indicator, tester). An instrument that lets you detect the presence of electrical voltage in a specific area of a circuit. It is used not only by professional electricians, but also by ordinary people engaged in independent installation of electrical wiring in their homes.
A voltage tester is used for the following purposes:
- Determining phase, neutral wire;
- Determining the polarity of battery cells and batteries;
- Finding hidden (walled-in) wiring in a wall;
- Finding a break in an electrical circuit;
- Checking operability of heating elements, incandescent lamps, diodes and other radio components.
In addition, by means of digital models of modern devices it is possible to determine the voltage value, the position of the positive and negative electrodes on the diode.
Why use an indicator screwdriver
This tool is necessary when you need to:
- Find out the causes of electrical breakdowns;
- Determine the location of the breakage of phase wires;
- understand the wiring;
- To check if an outlet is working;
- install a new socket;
- determine the purpose of the wires when connecting the electric circuit.
In other words, a pilot screwdriver is needed to precisely, but safely, detect the presence of electrical voltage in wires. Thanks to this device, repair and adjustment of electrical appliances and equipment, as well as the laying of electrical circuits is greatly facilitated.
Important to know: Do not use the indicator screwdriver as an ordinary screwdriver, as it can lead to the tool becoming unusable.
What the indicator screwdriver shows
This device indicates the presence of electric current in electrical appliances and wires. Such tools are necessary for independent safe determination of phase and zero.
The data on the indicator screwdrivers can be displayed:
Plain (simple) with a neon bulb
The simplest electric screwdriver is only good for checking if there is a phase. You can also call it an electrical tester (electrical probe), because with this device you can not do anything else. only “try” whether there is voltage or not. Zero is found only by elimination. It is also possible to detect a breakage (or missing contact in relay circuits), but the device must be energized for this to work.
There are two types of ordinary screwdrivers. They can be distinguished by their appearance. Some have only a stinger and a plastic handle, others have a metal contact plate at the end of the handle. The first type (without contact) is “self-contained”. To detect voltage, you only need to touch a live conductor with the stinger. if there is voltage, the light bulb lights up. But such probes are rare, more often they can be found for low voltage operation. 12-36 V. When using a second type of indicator screwdriver to see if there is a phase, you must additionally touch the contact pad on the handle with your finger. Without it, the indicator will not light up because no electric current flows through it.
The design of a simple indicator screwdriver
Before using an indicator screwdriver, it is advisable to know how it works. this will make it easier to use later. The design of a simple screwdriver to check electricity is not complicated at all. The circuit is as follows: screwdriver stylus, resistor (1 megohm), neon lamp, spring and contact plate/sensor as a button on the handle. When you touch the button, a circuit is formed of which your body is a part. As a result, the neon bulb lights up. The current flowing is very small, because it is limited by the resistance.
If you only need this functionality (to check the phase and find a break). this is one of the best options. And it is the most inexpensive. Costs such a screwdriver indicator from 20. Disadvantage. it will not show anything at low voltages. If the voltage is below 70-60 V, it is useless.
Checking the indicator for serviceability
Before you start, you need to test it to see if it works. It is enough to touch simultaneously the metal contact on the handle and the steel slotted rod of the screwdriver.
At the same time, the indicator light must light up. it means that the device is working, if it does not light up, then it does not. If you test an ordinary indicator screwdriver like this, nothing will happen.
Digital multimeter tester: how to use the device
This device is an improved version of the active indicator. This is a voltage tester. It can also be used like a normal device. Professionals call this tool a “multimeter” because it can perform several functions:
Such testers have switches that regulate the level of sensitivity. The device can be used in both contact and non-contact mode to determine the presence of voltage and voltages.
The device, in addition to the light, is also equipped with a sound signal. The device has a digital display that shows the measurement values.
Important! With a multifunction tester, it is easy to buy additional pliers, which can be used to determine the amperage without removing the insulation layer.
The digital multimeter tester is equipped with an electronic display
In order to have a confident idea of how to find phase and zero with an indicator screwdriver of this type, you should carefully study the description of the device and the instructions. Some models, in addition to the functions listed above, are capable of checking the temperature of energized equipment. Such capabilities are important for those who monitor the operation of electrical switchboards, electric motors, etc. д.
Cabinets, where the wiring comes from, are equipped with almost all modern homes. And relatively powerful motors are not uncommon in the household. That’s why it’s often necessary to have a multifunctional tester, and not a simple indicator screwdriver in everyday life.
Types of indicator screwdrivers and their construction
This simple device goes by many names. Some are more common than others. Here, the names that can be found :
How to work the indicator screwdriver depends on its type
Perhaps there are other names. this device, though not complicated and costs a little, is useful for professionals and amateurs alike. It can be used to determine the most common damages, check the continuity of wires and the functionality of radio elements.
You already know how to use the indicator screwdriver and what it can do. Now we need to know how to choose the right model. Even the most sophisticated screwdriver costs no more than 12-15 (this European manufacturers, the “Chinese” are three times cheaper). You can buy an ordinary one at all for 20 (about 25 cents). Despite this, it must also be chosen wisely. It is best to have two models in your household: a regular one as a phase detector and one with a contact type LED for testing and continuity of wires. The more “smart” models require constant practice, otherwise you’ll simply forget what to do and how to do it. And reading the manual every time is not the best option.
Looks very similar, but the functionality can be very different
Even if you have decided on the type of indicator screwdriver you want to buy, you must choose it according to certain parameters:
- For what voltage.
- If measurements are to be made on a single-phase line, the measuring range should be 70-250 V or 100-250 V.
- For three-phase networks there are models that can measure voltages up to 400 V.
- For low-voltage, there are 12-24-36V models, too.
These are actually all the options. The choice is not so complicated. The main thing is not to forget: before you use the indicator screwdriver, be sure to check its performance and follow electrical safety rules when working.
How the tool is checked
Like any device with measuring qualities, our signal screwdriver sometimes needs to check its performance.
Please note! Working with voltages always requires constant monitoring of the proper functioning of the measuring instrument.
To ensure that our signal tool is always ready to measure voltage, pay attention to the following nuances:
Please note! If there is damage to the housing, the product must be replaced. Otherwise your safety at work will not be guaranteed by the manufacturer.
- Always check that the tool is working correctly before you start working on it. It can be checked simply by touching a live conductor;
- Replace the batteries if they are flat. To do this, carefully unscrew the fixing cap and replace the old batteries with new ones. The main thing here is not to mix up their polarities. Otherwise the screwdriver will not function.
Repair with your own hands signal screwdriver, if found to be broken, will not be rational. cheaper to buy a new tool.