Definition and Function of Voltmeter

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Voltmeter Is ?  The following is an explanation of what a digital & analog voltmeter is, Functions, types, examples of images & how to read / use it

A voltmeter is a tool that may be often seen and used in everyday life. Besides being a mandatory device that must be owned by an electrical technician, this tool is also necessary for you to have at home.

What is the difference between a voltmeter and a multimeter? The most basic difference between a multimeter and a voltmeter is in the type of measurement of its electrical units. Multimeters can measure Amperes, Volts, and OHm, while Voltmeters are limited to measuring Voltages only (mV, kV).

Here are detailed understanding what a voltmeter is, types, working principles, and of course a tutorial on how to use a digital and analog voltmeter correctly.

What is a Voltmeter?

A voltmeter is an electronic device used to measure the electrical voltage in an electronic circuit. Generally voltmeter units are expressed in the form of Volts, millivolts (0.001 volts), or kilovolts (1,000 volts).

In addition to the above understanding, a Voltmeter can also be defined as a tool made to measure the electrical potential between 2 points in a system.

This measuring instrument must be installed in a parallel circuit with the ends of the resistance which will later be calculated how much the potential difference is. In this tool there is resistance, so that when installed it will make the electric current that will pass through the resistance slightly reduced.

As you already know that a voltmeter is a tool used to measure the amount of electrical voltage. Then ideally, in order to make the electric current passing through the resistance small, the resistance on the voltmeter should also be very large.

Voltmeter Images & Components


The voltmeter consists of certain parts that have different functions. The parts / components of the Voltmeter consist of a positive input terminal marked in red and a negative input terminal in black.

Then there is a pointing needle that shows the power voltage, the measuring limit, the high scale to the low scale and the function regulator setp (quantifier). Broadly speaking, the components of the voltmeter consist of:

  • Negative input terminal (generally black)
  • Positive input terminal (generally colored red)
  • Measurement Reading Screen (In digital models it is numeric, while for analog it is in the form of a scale needle)
  • Adjusting screws
  • Knob for selecting a measurement range
  • Ports / Plugs
  • Scale meter

Voltmeter Function


The main function of the voltmeter is to measure the amount of voltage value in the electrical circuit. In addition, the voltmeter also has another function, namely as a device to check electrical devices such as batteries or sockets whether they have electrical power or not.

In addition, there are other functions of the voltmeter function, including:

  • Measuring AC and DC Voltage

One of the other functions of a voltmeter is as a tool to measure the voltage value in AC and DC electric currents. This tool measures the value of the potential difference between two points contained in an electrical circuit.

  • Measuring the Flow of Electric Current

Besides being able to measure voltage values, this tool is also able to measure and display the amount of electric current flow in an electronic circuit.

  • Check Electrical Power

Besides being able to be used to measure voltage and electricity, another function of this tool is as a Tools Checker or a tool to check electronic equipment has electrical power (still alive) or not (it is dead).

This measurement of electrical power, for example, is used to check the socket, car battery and also the battery as in the example written by the Wikihow.com below.

Voltmeter Type

There are several types of voltmeters that are grouped by way of use and how to read them. The types of such types of voltmeters are analog and digital voltmeters.

In addition to having digital and analog types, based on the measurement method, voltmeters also have several types, namely Rectifier type voltmeter, Induction type, electrostatic
type, parmanent type magnet moving coil (PMMC), mobile iron type (MI), and also electro dynamometer type. Here’s the review:

Voltmeter Analog


This type is deflecting that signifies a voltmeter. This type is still divided into several more types based on its instruments. There is a moving coil instrument, which uses a permanent magnetic field so that it is only able to respond to direct current.

Furthermore, there are mobile iron instruments used in AC circuits. This type still consists of several more components, namely simple moving iron, the type of induction instrument and the type of attraction.

Voltmeter Digital


As the name implies, this type shows the results of readings in the form of digital numbers. Its accuracy is influenced by various factors, including the supply voltage and temperature.

This type is created by using a pre-programmed micro-controller. The results are then displayed on the LCD display. This type is claimed to be able to display accurate results.

Differences between Digital and Analog Voltmeters:

The main difference between digital and analog votmeters lies in the results of their measurements. In the digital voltmeter, the measurement reading results are displayed numerically on the LCD screen while in the analog type the measurement readings are displayed by the pointing needle.

Based on the previous explanation, it is stated that although the functions of the voltmeter are both the same, there are several things that distinguish the two. In addition to some differences in instruments as mentioned above, each of these types also has its own advantages and disadvantages.

The most significant difference is that in digital voltmeters, dc or Ac voltage measurements are carried out in the form of discrete numbers that are used to replace the continuous scale pointing needle on analog voltmeters. The use of discrete numbers is considered more profitable because it can minimize errors in readings.

In addition, with the output issued in digital form, it will make the process of reading potential differences faster. The resolution instruments are also higher with a higher level of precision as well.

Even by using this digital voltmeter, it can provide a more precise and accurate voltage value in one particular circuit compared to using an analog voltmeter.

Also Read: How to Determine the Type of TRANSISTOR NPN and PNP with Digital Multimeter

How a Voltmeter Works


The principle or way this Voltmeter works is basically similar to a Galvanometer but with the addition of a multiplier. The interaction between the strength of the current and the magnetic field will be able to give rise to magnetic forces.

Because the magnetic force is what then moves the pointing needle until it diverges when it is passed by the current through the coil.

The greater the strength of the current, the greater the deviation. While in the voltmeter the design is added with a multiplier resistance.

This multiplier resistance serves to hold the current so that the voltage that occurs does not exceed the maximum limit and the measurement ability is greater.

How to Use a Voltmeter


After knowing the parts of the voltmeter earlier, the next step is how to use and read the results of the voltmeter measurement. If you don’t know how to use it, here is an explanation of how to use a voltmeter correctly.

  • Components to be Measured Arranged in Parallel

A voltmeter is a tool used to measure potential differences. So, before taking measurements, components that have potential differences must be arranged in parallel first. At this stage, also adjust which current circuit should be in the same direction as the polar part of the voltmeter.

  • Positive Poles & Negative Different Potentials

If so, the next step is to make sure the positive pole and the negative pole have a potential difference. Of these two components, the positive pole has a higher potential, as does the negative pole that has a low potential.

  • Pay Attention to Deviations

If the installation is reversed, it can be easily noticed through deviations. Deviations that occur are characterized by when the position is reversed usually towards the left. After that, just read the measurement results.

As a tool related to electrical circuits, the voltmeter is one of the most frequently encountered measuring instruments in everyday life.

Also Read: Length Measuring Instruments

To better understand about this measuring instrument, a complete explanation of the functions, parts, how it works, types and differences between digital and analog voltmeters above hopefully can provide more information about this tool.

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