How Does a Voltmeter Work

If you need to determine the difference between one electrical source to another, a voltmeter will be able to measure it for you. These devices are not equally made. There are mounted types for the use of monitoring generators, and others permanently fixed. Just like the multimeter, they also have features that could measure resistance and the current and serves as primary testing tools when working with electricity and electrical components. A calibrated voltmeter displays the measurement made and transformed into a voltage. Such examples of values are temperature and pressure.


There are two types of voltmeters:


Digital voltmeters displays converted unknown inputs of voltage into digital values and featured them in numeric figures. Digital voltmeters are typically created with a converter from analog to digital also known as an integrating converter. When it comes to accuracy, factors such as impedance, temperature and voltage variations. Some digital voltmeters that can be purchased at a lower price already have the input resistance. But unlike those that are high precision voltmeters with a 1 GΩ on input resistance or better, regular ones only have 10 MΩ. These devices are regularly calibrated in a certain period to assure its accuracy.


Analog voltmeters are often galvanometers incorporated with resistors. A magnetic field embracing the coil floats in mid-air that may rotate once a flow of electric current triggers the magnet and the magnetic field to produce torque. The coil then moves against the spring with the current corresponding to the loop and is equivalent to the voltage that was applied.

You may be using either of the two, but in general, both follow Ohm’s Law that depicts the various relationships in a circuitry. Described with a formula, it makes use of the three electrical values in the following order: voltage divided by current equals resistance. Both types of voltmeters are used to measure a variety of benefits within a circuit.

How both types of voltmeters work

  • The analog voltmeter works this way:

A current passes through a suspended coil positioned between two magnets. The moving loop, as it is known, acts following the voltage when administered to the permanent magnets. The selected scale of energy that makes a value resistor positioned with other central measurements as Ohm’s Law now becomes enforced. As the voltage envelopes the coil, a magnetic field surfaces that oppose the magnets where the positioned pointer is in the middle. The tip now shifts accordingly to the opposing magnetic field. The pointer’s shifting is now equal to the voltage amount being given to the pointer pivot which that coil now wraps inside. Readings begin to be accurate enough to record, and the movement ceases. It is a specific type of voltmeter that is sensitive and sophisticated enough for both home and professional use.

  • Digital voltmeters come into the picture:

More user by far chooses this latest type of voltmeter because of its compatibility with today’s technology of digitized systems. Analogs are still around used by some professionals since it works for them in a way that digital voltmeters cannot satisfy. Still, there are reasons why some go for the modern touch. The converted AC and DC voltages turn into numerical figures by digital types, unlike analogs that use deflection of pointers to scale and present readings. The following are the benefits of choosing digital over analogs:

1) because of the numerical display, it is easier to read, and it eliminates approximation;

2) readings are done quickly;

3) data output can be stored away and be used as a future reference for the next computation;

4) accuracy and versatility;

5) inexpensive and lightweight, and

6) it doesn’t use up as much energy.

The key factor to the digital voltmeter is its ability to convert from analog. To be able to fully understand how this type does its magic, there are other functions to be checked around the ADC or analog-digital converter. The ADC is presented on average so that resolution and accuracy are prioritized. Electrical noise is canceled to achieve the highest possible accuracy. Digital voltmeters make use of specific times to fully convert the voltage to digital data such as switch time, settling time, signal measurement time, auto-zero time, and ADC calibration time. Because various manufacturers make these, the accuracies will differ by fractions, so it is better to know how they work to get the best possible conversion.