Tools

# How does a voltmeter work?

In electrical installations, one of the most important components is the voltmeter. But this can also be used in a particular way, as long as there are two electrical terminals, one positive and the other negative.

## What is a voltmeter?

voltmeter is a measuring instrument that allows knowing the difference in potential or voltage between two points in an electronic circuit.  The unit of measurement for voltage is the volt (V).

Voltmeters are made up of a galvanometer to which a series resistor is added . Depending on the range of volts you can measure will be your cable structure and insulation.

## What is a voltmeter used for?

Briefly, a  voltmeter measures the potential difference between two terminals. This can be used to measure the voltage at two points in a circuit safely and without changing the circuit conditions.

On the other hand, the verification of the voltage that we obtain with the use of a voltmeter, allows us to verify if, for example, the plug in our house is working correctly or if it is damaged.

– EXAMPLE : Suppose that the potential of the electrical network is 220V. If after a measurement we see that the voltage is 150V, this is a symptom that the plug is damaged or that the electrical network is not delivering the correct power .

## How does a voltmeter work?

The voltmeter consists of a very high resistance, made up of a fine wire with many turns that forms a coil . This means that by connecting the voltmeter in parallel to the circuit, the least amount of current possible circulates through the voltmeter and does not affect the behavior of the circuit, and by having many turns, the coil generates the necessary force to move a needle.

Generally, the voltmeters come inside the testers, and to make a measurement, you must place the tester terminals at the points where you want to measure the voltage.

Previously, the voltage range to be measured must have been placed in the tester. Once the terminals are connected, the tester needle will show the voltage value.

## Voltmeter types

There are different types of voltmeters that can vary depending on their operation, the scale they use or the way they display the results. Next we will show the different types of voltmeters.

### Electromechanical voltmeters

They consist of a galvanometer with a graduated scale in volts. It can be adapted to direct current or alternating current .

### Vector voltmeters

Used in currents with microwaves since they also allow the phase in which they are to be shown.

### Digital voltmeters

They are voltmeters that allow a reading of the measurement numerically on a screen and not with an indicator needle.

## Differences between voltmeter, ammeter and multimeter

The voltmeter is an instrument used to measure the voltage between two electrical terminals . On the other hand, the ammeter is similar but measures the intensity of the current that passes through a point in the circuit .

multimeter integrates these two principles in the same instrument , including more functions such as resistance or capacitor meters, galvanometer, etc.