Voltage testers are one of the very essential tools every home handyman should carry. It is among the basic tools and is required to measure the actual voltage. Measuring the voltage is the initial step before working on any electrical equipment, thus being considered as a very important task as well. Voltage is the potential difference between two points in an electrical circuit. It is actually the measure of capacity of an electrical field to cause an electric current in an electric field. Thus it is very important to know the exact capacity of electric field to ensure smooth working of that electric field which in turn will enable the electrical equipment where it is being installed to run smoothly.

Working principle

According to ohm's law the resistance across a circuit is proportional to the potential difference between the positive and negative point of a circuit. Thus to measure a potential difference across the electrical circuit the current is passed through another circuit which has got fixed resistance. Thus the resistance gives the measure of the potential difference across the circuit, which is the measure of the voltage.

How to use a voltage tester

First insert the voltage tester in a receptacle that you know for sure is live. As soon as the voltage tester is inserted it will give a flash or beep or may be both according to the nature of the instrument, this step is to ensure that the tester is certainly working or else a dead battery in the tester may sometimes give the impression that a circuit is dead and safe to work upon when it is still alive. Move to the electrical receptacle, which you wish to test. Insert the tip of the voltage tester to both the slot of the electrical receptacle. The voltage tester will respond in a flash or beep sound or may be both according to the nature of the instrument establishing that the circuit is still alive and show the potential difference across the circuit if it is a digital one. To test an electrical cord one has to hold it against the wire, which generally is constituted of three, wires the positive, the negative and the ground wire. The voltage tester shows current only against the positive wire.

While operating a voltage yester on any electrical equipment safety should be given the prime importance. Euro 2 standards should be followed to ensure this. A new age testers called the two pole testers are there which makes the operation much easier and safer.