What Is Current? | Purpose, Unit and Practical Applications Explained

Electricity powers our modern world, providing us with the means to light our homes, run appliances, and operate electronic devices. At the heart of this phenomenon lies the concept of electric current. 

In this article, I will explore what is current, how it works, its types, and its significance in various applications.

Key Takeaways

  • Electric current is the flow of electric charge through a conductor and is measured in amperes (A)
  • Electric current flows due to the presence of a voltage difference that creates pressure for the flow of electric charge through a conductor.
  • Direct current flows in one direction, while alternating current periodically changes its direction.
  • Voltage plays a crucial role in generating current by providing the necessary force for the flow of electrons in a circuit.
  • Electric current offers numerous advantages, including versatility and efficient energy transmission, but it also presents risks and potential energy losses.

What is Current?

Electric current is a fundamental concept in the field of electricity and plays a crucial role in our daily lives. It is essential for powering electrical devices, from small household appliances to large industrial machinery. The flow of electric charge occurs when there is a potential difference, or voltage, across a conductor. This voltage creates an electric field that exerts a force on the charged particles, causing them to move. In most cases, the charged particles involved in the current are electrons, which are negatively charged. However, in some situations, such as in electrolytic cells, positively charged ions can also contribute to the flow of current.

The unit of measurement for electric current is the Ampere or Amp (A), named after the French physicist André-Marie Ampère. One Amp is defined as one coulomb of charge passing through a point in a circuit per second. In practical terms, this can be visualized as the number of electrons passing through a given point in a wire within a specific time frame.

Electric current is typically represented by the symbol "I" and is measured using an ammeter. Understanding the concept of electric current is crucial for electrical engineers, physicists, and anyone working with electricity to design and analyze circuits, calculate power consumption in Watts, and ensure the safe and efficient operation of electrical systems.

A person measuring the electric current

Electric Current: The Flow of Electric Charge

In an electric circuit, current is a result of the presence of a voltage difference or potential difference across the circuit. When there is a voltage applied to a circuit, it creates an electric field that exerts a force on the charged particles within the conductor, enabling the flow of electric charge.

This force is analogous to the pressure difference that drives the flow of water through a pipe. The voltage, measured in Volts, acts as a driving force, pushing the electric charge through the circuit.

To facilitate the flow of electric charge, conductors are typically used in electrical circuits. These conductors contain charge carriers, usually free electrons that are loosely bound to their atoms. When a voltage is applied, the electric field acts on these charge carriers, causing them to move in a specific direction, thus establishing an electric current. The flow of electric charge, or current, is measured in amperes (A).

A person holding the wires

An interesting phenomenon associated with electric current is the production of a magnetic field. Whenever there is a flow of electric charge, a magnetic field is generated around the current-carrying conductor.

The strength of the magnetic field is directly proportional to the magnitude of the current. This principle is utilized in various applications, such as electromagnets and electric motors, where the interaction between the current-carrying conductors and the magnetic field produces useful mechanical effects.

Understanding the relationship between voltage, current, and magnetic fields is crucial in the study and application of electricity. It allows engineers and scientists to design and analyze circuits, develop electrical devices, and harness the power of electricity in a wide range of technological advancements.

Types of Electric Current: Direct and Alternating

There are two main types of electric current: direct current (DC) and alternating current (AC).

  • Direct Current (DC): In a direct current circuit, the flow of electric charge occurs in one direction only. The electrons flow from the negative terminal of the energy source (such as a battery) towards the positive terminal. DC is commonly used in electronic circuits and batteries.
  • Alternating Current (AC): In an alternating current circuit, the flow of electric charge periodically reverses direction. The current continuously oscillates, changing its polarity. AC is the type of current used in power lines and most household appliances.
  • A power inverter changes direct current (DC) power from a battery, usually 12V or 24V, into conventional mains alternating current (AC). This means that you can use a power inverter for power tools on the go and various electronic devices, kitchen appliances, or as a convenient way to keep your devices charged while camping.
Schema of DC and AC current

How Current is Generated: The Role of Voltage

To generate electric current in a circuit, an energy source such as a battery or generator is essential. These devices serve as the providers of potential difference or voltage required to establish a flow of electrons. The energy source acts as a power supply, creating a "push" for the electrons within the circuit. Voltage creates pressure that drives electrons in a single direction.

When a circuit is complete, meaning it forms a closed loop, and a voltage is applied across it, the electrons within the conductor experience a force. This force acts in the same direction as the potential difference or voltage applied to the circuit. As a result, the electrons are propelled forward, initiating the flow of electric current.

The voltage from the energy source creates an electric field that exerts a force on the negatively charged electrons. This force overcomes the resistance within the circuit, allowing the electrons to move from the negative terminal of the energy source to the positive terminal.

It is important to note that while the electrons themselves move in the opposite direction to the current flow, the conventional direction of current is considered as the movement of positive charges.

By providing the necessary push for the electrons to move, the energy source enables the establishment of a continuous flow of current in the circuit.

This is the fundamental principle behind the operation of various electrical systems and devices, from simple circuits powering light bulbs to complex electronic devices driving advanced technologies.

One ampere of current represents one coulomb of electrical charge (6.24 x 10 18 charge carriers) moving past a specific point in the circuit in one second.


  • An electric current is a versatile form of energy that can be easily controlled and directed through electronic circuits.
  • It enables the efficient transmission of electrical energy over long distances through power lines.
  • Electric current powers various devices and technologies, ranging from everyday appliances to complex industrial machinery.


  • Current flowing through a circuit generates heat, which can be wasteful and potentially lead to energy losses.
  • Improper handling of current can cause electrical hazards and pose a risk of electric shock.
  • Frequently Asked Questions (FAQs)

    What direction does the current flow?

    Electric current flows from the positive terminal to the negative terminal of an energy source, despite the actual movement of negatively charged electrons being in the opposite direction. This is known as conventional current flow.

    How can we measure current?

    Current can be measured using a device called an ammeter or by using a digital multimeter in the appropriate current measurement mode.

    What is the relationship between current and voltage?

    According to Ohm's Law, the current is directly proportional to the voltage and inversely proportional to the resistance in a circuit. The relationship can be expressed as I = V/R, where I is the current, V is the voltage, and R is the resistance.

    Final Words on Current

    Understanding electric current is essential for comprehending the functioning of electrical systems. Current represents the flow of electric charge through a conductor and is the backbone of various technologies we rely on daily.

    By grasping the concepts of current, voltage, and circuitry, we gain insight into the fundamental principles that govern the world of electricity and its applications.

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