The indicator screwdriver is a convenient and simple device that allows you to establish the presence of voltage in the electrical network. Some models are capable of detecting even an open circuit. They work on the principle: contact, capacitor, indicator. The voltage is applied to the screwdriver contact, passes through the capacitor and enters the indicator.
An indicator screwdriver can come in handy when it is necessary to carry out work with electrical circuits, determine the phase or neutral wire, and detect damage to the network. Such a device is used both for domestic purposes and for solving professional problems. The possibilities depend on the complexity of the model and, accordingly, on the cost of the product.
There are 3 main types of indicator screwdrivers:
- with a neon bulb;
- with LED;
- with an electronic board.
Neon light indicator screwdrivers
The principle of using the simplest model is as follows: with the tip of a screwdriver, they touch the surface of the conductor (for example, a terminal in the socket), and a finger clamps the contact on the insulating handle of the indicator screwdriver. In this case, an electric current enters the sting of the tool, passes through a resistor, and is supplied to the bulb contact.
In the scheme of work, the resistance of the human body and its electric capacity are directly involved, since the contact on the screwdriver is closed with a finger. In fact, a person acts as a capacitor.
If voltage is present, then the neon bulb will light up, otherwise no changes will occur. Such a screwdriver will fix an electric circuit with a voltage of over 60 volts, and this is a significant limitation.
LED indicator screwdrivers
LED screwdrivers work just like neon ones. The main difference that speaks in favor of the neon model is its ability to respond to voltages below 60 volts.
Battery-powered devices equipped with a bipolar transistor are available. Such screwdrivers can not only determine the phase and open circuit, but also detect the point of damage in the conductor. There are models that can capture microwave radiation.
