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It may not happen every day, but trust me, when the electrical circuits you're working with show faults or leaks, you'll want to have one of these around. T

hroughout this article, I will try to show how essential this tool is not only for electricians, but also for anyone who needs to perform daily checks on their equipment. As in almost all cases, there are many such instruments. And each case presents very interesting options for different types of budgets, users and jobs.




Summary

  • Ammeters are tools that allow you to know the numerical value of the electric current circulating within an electrical system or equipment.
  • Ammeters allow you to detect losses or faults in the electrical system by measuring an amperage that will indicate a differential. By measuring different parts of the circuit specifically, this differential will allow us to establish a starting point, to detect the precise location of the loss or fault.
  • When making a purchase, certain criteria must be taken into account. These include safety, accuracy, the ability to measure both voltage and current and, of course, the price-quality ratio.

The Best Ammeter: Our Picks

Buying guide: What you need to know about ammeters

If you are looking to keep an eye on the electrical systems you are working with, it is essential that you know some of the features of ammeters. This way, you will be able to make a purchase that meets your needs. Below, we will show you a set of common questions among users, in them you can find data that will be very relevant to you when making a purchase or using your product.

electricistas trabajando en instalación

To connect an ammeter we will have to connect it in series with the power supply and the actual receiver. (Source: auremar: 13782943 / 123rf.com)

What is an ammeter?

An ammeter is an instrument for detecting small amounts of current. A DC ammeter consists of the moving coil galvanometer and a parallel resistive (shunt) arrangement to make up each of the ammeter's scales (3).

This is because this tool has a very small internal resistance, so it does not decrease the measured current when connected to a circuit. Today, ammeters often use a digital converter that is read by a built-in microprocessor. Although the result is the same, it will let you know the numerical value of the electric current flowing within an electrical system or equipment.

What is an ammeter used for?

In general, ammeters are mainly used by electricians. Although it is one of the most sought-after tools on the market, this is due to the growing presence of electrical systems in different areas.

This instrument will allow you to detect losses or faults in the electrical system by measuring an amperage that will indicate a differential.

Through the specific measurement of different parts of the circuit, this differential will allow us to establish a starting point to detect the precise location of the loss or fault. Once this has been done, the only thing to do is to repair it.

electricista trabajando en cableado

Ammeters allow you to perform electrical work more safely. (Source: Антон Дмитриев: y4aUBTWgzgQ/ Unsplash.com)

What types of ammeters are there?

There are five classes of ammeters, this classification is based on the measurement systems and therefore the usefulness each has. We could talk at length about each of them, but we will try to summarise them in a clear and concise way. Below, we present them to you:

  • Magnetic ammeters: Used to measure the current flowing in a circuit, the ammeter must be connected in series with the power supply and the current receiver. The limit value of what can be measured without fear of introducing errors is around 100 milliamps.
  • Electromagnetic ammeters: These are the most commonly used. They are based on measuring the interactions between magnetic fields and currents. The range of values covered by this type of ammeter goes from 0.5 A to 300 A.
  • Electrodynamic ammeters: These consist of two coils, one fixed and one moving, which produce magnetic fields, the reaction between them providing the torque needed to measure the circulating current. Again, the range of values that can be measured with this type of ammeter goes from 0.5 A to 300 A.
  • Digital ammeters: These instruments use a shunt resistor and an analogue-to-digital converter. The actual range they can measure is indeterminable.
  • Rectifier ammeters: These are used to measure alternating current which is connected to a secondary current from a current transformer. It is connected with a rectifier bridge to a moving coil ammeter. They have a measurement limit of about 500 milliamps.
How it measures current Error-free measurement limit
Magnetic ammeters You have to connect the ammeter in series with the power supply and the current receiver About 100 milliamps
Electromagnetic ammeters They are based on measuring the interactions between magnetic fields and currents From 0.5 A to 300 A
Electrodynamic ammeters They consist of two coils, one fixed and one movable, that produce magnetic fields, the reaction between them provides the necessary torque to measure the circulating current From 0,5 A to 300 A
Digital ammeters They use a shunt resistor and an analogue-to-digital converter It is indeterminable
Rectifier ammeters They measure the alternating current that is connected to a secondary current from a current transformer. It is connected with a rectifier bridge to a moving coil ammeter measurement limit around 500 milliamps.

How is the ammeter connected?

This is one of the most frequently asked questions and perhaps one of the most important. If we connect our ammeter the wrong way, it may not work. Worse yet, it may even give erroneous data. To connect an ammeter, we have to connect it in series with the power supply and the current receiver. In this way, the current flowing between the two points will pass through the ammeter allowing the current flowing through a circuit to be measured.

testeando el voltaje de una bateria

Ammeters are available at hardware and appliance shops. (Source: Norasit Kaewsai: 70202695/ 123rf.com)

Which is better, a voltmeter or an ammeter?

In principle, this question is a bit misleading as this will depend on the task you are looking to perform. Both instruments are used for different tasks. For this reason, the differences between the two will be explained as fully as possible.

  1. The ammeter is a device used to measure current flows in a circuit. The voltmeter measures the difference in power between two points in a circuit
  2. An ammeter is connected in series with respect to the circuit to be measured. A voltmeter is connected in parallel with respect to the circuit.
  3. An ammeter is usually more accurate than a voltmeter.
  4. The measuring range of an ammeter is not variable, whereas the measuring range of a voltmeter may increase or decrease as the value of resistance changes.
Type of use Connection type Accuracy Measuring range
Ammeter Measures the flow of current in a circuit Connects in series More accurate Not variable
Voltmeter Measures the difference in power between two points in a circuit Connects in parallel Less accurate Variable

What happens if I connect the ammeter in parallel?

As explained above, ammeters are instruments that are connected in series with respect to the circuit being measured. This is because the internal resistance of an ammeter is very low.

This would cause a short circuit and therefore the ammeter will be at risk of becoming unusable.

Although most of these instruments have a fuse, if the short circuit current is too high, the ammeter can end up broken.

In conclusion, if an ammeter is connected in parallel, the current flowing through the ammeter will be very high in relation to its internal resistance

Purchase criteria

If you are thinking of buying an ammeter, it will be vitally important to follow certain buying criteria. Below, you will find some of what we consider to be the most important when analysing the items you will find on the market.

Accurate

Nowadays, ammeters have a digital display, which has greatly improved the accuracy of these instruments. While the ammeter is a precision instrument, it is also an instrument that indicates the direction of the current (1).

It is important to take into account the indication of the direction in which the current is flowing, as just knowing the amount of current may be insufficient. Fortunately, ammeters of recent designs have both of these data, in addition to various functions and features. Therefore, when making a purchase, it is always advisable to opt for modern designs with LED displays and multifunctional functions.

Of course

Perhaps the most important element to keep in mind when working with electric current is safety. Especially as ammeters can be used for both direct and alternating current tasks. That's why we recommend you buy ammeters with an NCV function, which allows you to avoid contact with cables and power lines for a safer measurement. It is also important to highlight products that come in the form of an armband, as they provide a certain distance between the user and the current.

Current

Current level measurements are generally made indirectly for low power. While all ammeters will have the ability to measure current flow, not all will have "A" type accuracy. You will need to ensure that the AC current ranges and maintain a degree of "A" accuracy so that they are close to the following values: 6A / 60A / 600A ±(2.5% + 10).

Voltage

Ammeter technology has advanced to the point where they can now not only measure current flows in a circuit. They also come with the function of detecting the voltage values of a circuit. However, not all ammeters have the ability to measure both DC and AC voltage, so this will be another issue to consider when making a purchase. Whether you are thinking of buying an ammeter for your automotive mechanics or are looking to install/control a photovoltaic circuit. We recommend that you buy an ammeter that fulfils both functions as they will be useful in the short or long term.

probando amperímetro en auto

Ammeters are tools that will let you know the numerical value of the electric current. (Source: Philippe Renaud: 93952907 / 123rf.com)

Cost Benefit

Finally, our criteria include cost-effectiveness. As described above, there are a wide variety of functions that an ammeter can have. It is these functions that generally determine the price of these products. Therefore, it is important to keep in mind the tasks you are looking to perform with the ammeter. If you want to perform simple tasks, it may not be necessary to spend a lot of money on a product that will never be finished because of its many features.

Summary

In general terms, ammeters are instruments for detecting small amounts of current. However, the need for more and more complete tools has led to the incorporation of several functions, such as the possibility of measuring different types of voltage. It is always necessary to take into account the degree of accuracy of these tools.

In addition, perhaps the most important aspect to be taken into account is the safety it provides, as it should never be forgotten that we are talking about working with electrical energy with all that this implies. Finally, if you think that this guide has been useful. Please leave a comment and share it with your contacts. Not only are you helping us, but you may also be improving someone else's shopping experience.

(Featured image source: akz: 93485124/ 123rf.com)

References (1)

1. Forrero Laguna JA, Chaves Osorio JA, Castro Hernández OE. AMPERÍMETRO DIGITAL DE BAJA POTENCIA IMPLEMENTADO CON MICROCONTROLADOR PIC16F877A [Internet]. https://www.redalyc.org/pdf/849/84916714037.pdf. Scientia Et Technica; 2009 [cited 2020].
Source

Artigo científico
Forrero Laguna JA, Chaves Osorio JA, Castro Hernández OE. AMPERÍMETRO DIGITAL DE BAJA POTENCIA IMPLEMENTADO CON MICROCONTROLADOR PIC16F877A [Internet]. https://www.redalyc.org/pdf/849/84916714037.pdf. Scientia Et Technica; 2009 [cited 2020].
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