# Electrical measuring instruments, what are they?

When we talk about instruments to measure electrical energy it is normal to think only of the multimeter or clamp meter, after all these are one of the most used equipment and that practically every electrician has at least one of the two measuring instruments.

In addition to the multimeter and clamp meter, do you know other measuring instruments used in electricity and do you know what they are for? We will cover the most used measuring instruments in electrical, show their respective applications and what is the difference between certain measuring instruments. Come on!

## Measuring instruments

Measuring instruments or measuring instruments, as the name suggests, are devices used to measure certain quantities. The different types of the electrical measurement instruments can be field or bench, analog or digital and with different degrees of precision. Among the different types of measuring instruments, we can cite as an example:

• Multimeter
• Pliers ammeter
• Thermometer
• Voltmeter
• Ammeter
• Ohmmeter
• Wattmeter
• Frequency meter
• Capacitor
• Inductimeter
• Oscilloscope
• Spectrum analyzer

The number and variety of electrical measurement instruments is enormous, and each of these instruments has different applications and characteristics, even though they are equal types of instruments, such as multimeters, which even being capable of measuring the same quantities serve service and for another, no. An example of this are the categories of multimeters.

In this article, we will present the general concepts and applications of some electrical measurement instruments.

Measuring instruments, types and applications.

## Measuring instruments – Operating characteristics

With these measuring instruments, we can evaluate, control and transmit the electrical quantity to be measured, but for this purpose two operating characteristics of these devices are essential, which is accuracy and precision, where:

The Accuracy of a measurement instrument is how close the value indicated by the instrument is close to the exact value, that is, that we expect to measure. For example, if we want to measure the voltage of a battery that actually has 9V, when doing this measurement we hope to find something around it, like 9.1 or 8.9, so the measured value is very close to the true value.

The precision of a measurement instrument is what says if the measured values ​​are close to each other, however it is not necessary that these measurements are close to the true value.

Following the previous example, when making some measurements under the same conditions for example, we could find 9.30V, 9.31 or 9.33 for example. So this instrument is accurate, because the measurement values ​​are close, but the true value or that we want to measure is 9V and the samples are indicating values ​​close to 9.3V, that is, we can conclude that this instrument is accurate, but it is not exact.

If the true value were 9.3V, that is, if we wanted to measure 9.3V this instrument would be precise and exact.

## Measuring Instruments – Multimeter

The multimeter is the device responsible for measuring various electrical and even non-electrical quantities through the use of sensors, such as measuring temperature using a thermocouple.

Multimeters have several functions and in addition to traditional measurements of voltage, resistance, current and continuity, we can find in a good multimeter options to measure frequency, temperature, capacitance and inductance for example.

## Measuring instrument – Clamp meter

Measuring electrical current with a multimeter is not very simple and safe, in addition the vast majority of multimeters do not have the ability to measure electrical current greater than 20A and it is also necessary to section the circuit to measure electrical current, ie , due to these circumstances it is impracticable to measure electrical current with a multimeter.

To solve this problem there is an instrument called a clamp meter, which facilitates the measurement in situations in which it is difficult to interrupt the circuit, perform current measurement with high values ​​and ensure the safety of the person making the measurement.

The coils present in the “arms” of the pliers identify the variation of the electromagnetic field, so the electric current is calculated by the device and displayed on the display. In addition to measuring electrical current, the clamp meter is also capable of measuring electrical resistance and electrical voltage.

## Measuring instruments – Terrometer

The terrometer is an instrument capable of measuring the resistance of the electrical ground , being a very sensitive instrument and that requires care when being handled.

Among the many applications of the earth meter the most common ones that we can highlight are: the measurement of earth resistance in industries, buildings, homes, SPDA systems, antennas and substations, allowing to evaluate the quality of a grounding system, such as efficiency grounding system.

## Measuring instrument – Wattmeter

The wattmeter is an instrument made to measure electrical power, power factor, harmonic distortion, resistance, temperature, frequency, voltage and current. Being a very versatile instrument, as it contains several features for different applications

## Measuring instruments – Oscilloscope

The oscilloscope is a measuring instrument that allows visualizing, on a display, electrical signals, that is, waveforms. With the oscilloscope, it is possible to use the instrument’s resources to obtain complete information that is extremely relevant for a given application, such as determining voltage and time values ​​of a signal; determine the frequency of a signal, determine the continuous (DC) and alternating (AC) component of a signal, detect noise interference in a signal and eliminate it, in addition to being able to trace characteristic curves of circuits and components.

The video below is from the Mundo da Elétrica channel, where it is taught step by step to survey the characteristic curve of a diode.