All about ammeter

With the advancement of technology and the continuous development of various industries related to the electrical field, the need for greater accuracy and precision in measuring and controlling electrical currents has increased. In this regard, tools such as ammeters are employed as key instruments in measuring electrical current.

Ammeters are devices that function as electrical current measuring instruments in electrical and electronic circuits. By measuring the current, these devices enable the detection of the amount of current passing through a specific point in a circuit, providing essential information for evaluating and controlling circuits and electrical equipment.

This article will delve deeper into ammeters, their operating principles, various types, applications, and their role in different industries. Additionally, we will introduce the top brands related to ammeters.

By reading this article, readers will gain a better understanding of this vital tool and become informed about the latest technologies and applications associated with it.

 History of Ammeters

Ammeters, essential tools for measuring electrical current, have a rich history of evolution and innovation, ranging from the earliest mechanical and magnetic methods to the modern advanced digital techniques.

 Early Use of Ammeters

The initial use of ammeters as precise instruments for measuring electricity, particularly electrical current, emerged with the invention of the battery by Alessandro Volta in 1800. This invention marked a pivotal moment in the history of electricity and signaled the beginning of its practical application. Early ammeters were primarily based on galvanometers, which utilized magnetic principles to measure electrical current. However, these early ammeters were mainly used in laboratories due to their sensitivity to external magnetic fields.

 Evolution of Ammeters from the Beginning to Today

In 1866, Edward Weston addressed the limitations of galvanometers by introducing a portable DC voltmeter with an accuracy of 0.5 percent. This significant advancement in electrical measurement technology paved the way for more precise and practical ammeters. The subsequent development of the moving coil galvanometer (PMMC) in the 1880s further advanced this field. This innovation allowed for the use of ammeters and voltmeters, offering benefits such as portability and independence from the Earth’s magnetic field. However, these early ammeters were still heavy, required multiple units to measure different ranges of amperage, and could not store data. They were also susceptible to heat and vibrations, which could affect their accuracy.

By the late 19th century, improved ammeter designs were developed that could be installed in any position and allowed for accurate measurement in electrical power systems. Generally, ammeters are represented by the letter “A” in circuit diagrams.

The history of ammeters also includes the development of digital multimeters in the 1970s, which marked a significant shift toward more precise and convenient measuring devices. By the 1990s, the number of digital multimeters surpassed that of analog or magnetic meters. In the 2000s, many companies began producing them, with some models costing as low as 90 cents per unit, while others made by reputable brands had higher prices.

In summary, the history of ammeters testifies to the evolution of electrical measurement technology, from the early galvanometers to the development of stable and accurate moving coil and moving iron ammeters, and ultimately to the widespread adoption of digital multimeters.

 Definition and Functioning of Ammeters

An ammeter is an instrument used to measure electrical current in a circuit. Due to this application, it is named an ammeter. The primary function of an ammeter is to directly measure the electrical current passing through the circuit being measured.

In the design of the simplest ammeters, an internal resistor is added to the circuit, and the circuit current passes through this resistor. According to Ohm’s Law, the voltage, which is directly proportional to the current, is measured by a voltmeter (the voltage measuring component) and converted to the equivalent current value.

Modern ammeters feature more complex electronic circuits that measure electrical current and usually have digital displays to show the measured values. These devices generally have the capability to measure both alternating current (AC) and direct current (DC) and typically can measure currents less than one milliampere.

Some ammeters have shunt resistors through which the electrical current flows. These resistors are placed in parallel with the current measuring device, allowing it to measure larger currents.

Ammeters are typically connected in series with the circuit being measured. This means that the electrical current flows through the ammeter and then returns to the circuit. When the current passes through the internal circuit of the ammeter, the amount of this current is measured by the ammeter and displayed on an indicator, such as a needle or an electronic display.

One of the important features of ammeters is their usually low resistance, which prevents significant voltage drop in the measured circuit. This characteristic is particularly important because voltage drop can affect the accuracy of the current measurement by the ammeter.

Ammeters are used to measure smaller currents, such as those in the milliampere or microampere range, and are typically referred to as milli-ammeters or micro-ammeters.

To measure larger currents, ammeters are usually connected to the circuit using a current transformer or a resistor known as a shunt. The current transformer or shunt allows the larger current to be measured safely, sending only a small portion of the current to the ammeter.

Ammeters should not be connected directly to a voltage source because their internal resistance is very low. This could cause excessive current to flow, which could damage the accuracy of the current measurement by the ammeter.

Read more: Review of Various Best Practices in Testing Electrical Panels

Types of Ammeters

There are various types of ammeters designed for measuring electric current, each suited for different applications and requirements. Below is a summary of the most common types of ammeters:

Analog and Digital Ammeters:

Analog Ammeters: These use a moving coil or moving iron mechanism to display the current value. They are simple, inexpensive, and reliable.

Digital Ammeters: These employ electronic circuits to convert the measured current into a digital readout, offering higher accuracy and precision.

Moving Coil Ammeter:

This type uses a coil suspended in a magnetic field, where the current passing through the coil causes a mechanical deflection of a pointer on a calibrated scale.

Moving Iron Ammeter:

This type uses a piece of ferromagnetic material that moves in response to the magnetic field generated by the measured current.

Rectifier Type Ammeter:

Used for measuring AC current, this type employs a diode or other rectifier to convert AC to DC.

Clamp Meter:

A clamp meter uses a magnetic sensor to measure the magnetic field generated by the current passing through a wire, making it useful for measuring current without directly inserting the ammeter into the circuit.

Thermal Ammeter:

This type measures current by detecting the heat produced by the current flowing through a wire, making it suitable for high current applications.

Electrodynamic Ammeter:

This ammeter uses fixed and moving coils to measure both AC and DC currents with high accuracy.

Hot Wire Ammeter:

This ammeter allows for direct measurement without the need for physical contact between the measured wires and other elements in the circuit.

Integrated Ammeter:

These ammeters offer similar advantages to digital ammeters and can provide accurate measurements at very low voltage levels.

Ammeters are vital tools for measuring electric current and providing essential information for evaluating and controlling electrical circuits and equipment. Their design and functionality have evolved significantly, from basic mechanical and magnetic methods to advanced digital techniques, reflecting the ongoing advancement in electrical measurement technology.

 Applications of Ammeters

Ammeters are extensively utilized in the electrical industry, science, technology, and daily applications such as in homes, vehicles, and electrical devices. Their uses include:

Measuring Electric Current:

The primary function of ammeters is to measure electric current in electrical circuits. This measurement can be for both direct current (DC) and alternating current (AC).

Fault Detection in Circuits:

Ammeters can serve as tools for diagnosing faults in electrical circuits. By measuring current, strong and weak points in the circuit can be identified, aiding in troubleshooting.

Evaluating Electrical Device Performance:

In the maintenance and repair of electrical devices, ammeters are used to verify proper operation. Measuring the current helps quickly identify issues and weaknesses in the device.

Energy Consumption Determination:

Ammeters can measure energy consumption in homes, factories, and other locations. By monitoring the current usage, energy consumption can be evaluated and optimized.

Industrial Applications:

In various industries, including electrical, electronics, automotive, and construction, ammeters are used to control and monitor electrical currents.

Laboratory and Research Applications:

In laboratories and research settings, ammeters are essential tools for measuring electrical currents in experiments and studies.

Household Applications:

At home, ammeters can be used to check battery status, measure current in electrical devices, and assess the performance of chargers and other power supplies.

Ammeters are vital tools in numerous applications, providing essential information for evaluating, controlling, and maintaining electrical circuits and devices across various fields. Their ability to measure current accurately makes them indispensable in both professional and everyday contexts.

 Top Ammeter Brands

Here are some of the best brands and models of ammeters:

Klein Tools

Klein Tools is renowned for its durable construction and wide range of tools. The MM420 TRMS Auto-Ranging Digital Multimeter is one of the standout products from this brand, valued for its accuracy, compact design, and versatility in handling various electrical projects.


Fluke is recognized as a leader in the multimeter market, offering various models to meet different needs. The Fluke 117/323 Combo Kit, which includes an AC/DC Voltage Multimeter and a Clamp Meter, is favored for its versatility and build quality. It features a magnetic hanger for easy measurement, test leads, and a carrying case.


The Amprobe AM-530 True-RMS Electrical Contractor Multimeter is noted for its versatility and extensive measurement options. This multimeter is ideal for complex tasks requiring more than basic testing, including measuring current, AC and DC voltage, resistance, frequency, and duty cycle.


The Innova 3320 Digital Multimeter is appreciated for its additional features. This multimeter is a top choice for users seeking a tool with useful extra functionalities and is suitable for a wide range of applications, from simple to complex electrical projects.

These brands and models are highly regarded for their performance, reliability, and user-friendly features, making them excellent choices for those seeking precise measurement tools in the electrical field.


AstroAI is recommended for beginners due to its ease of use and affordability. This brand covers all the essential measurements typically needed by homeowners or DIY enthusiasts.

 Notable Brands and Models

These brands and models are highly regarded for their performance, reliability, and user-friendly features, making them excellent choices for those seeking precise measurement tools in the electrical field.


With the rapid advancement of technology and the development of various industries, the need for greater accuracy and precision in measuring and controlling electrical currents has become increasingly important. Ammeters serve as vital tools in measuring electrical currents, providing essential information for evaluating and controlling electrical circuits and equipment. This article delves deeper into ammeters, their operating principles, various types, applications, and the top brands in the market.

By reading this article, readers will gain a better understanding of ammeters and their role in measuring electrical currents, and they will become familiar with the latest technologies and applications. This article serves as a comprehensive guide for individuals looking to choose and use ammeters effectively.

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