What Is Terminal Voltage?

Juliet D'cruz

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What Is Terminal Voltage

Are you curious to know what is terminal voltage? You have come to the right place as I am going to tell you everything about terminal voltage in a very simple explanation. Without further discussion let’s begin to know what is terminal voltage?

In the world of electrical circuits and power systems, voltage is a critical parameter that governs the flow of electricity. Terminal Voltage, also known as load voltage or output voltage, is a fundamental concept that plays a pivotal role in understanding how electrical devices and systems function. In this blog, we will explore the concept of terminal voltage, its significance, and its impact on the performance of electrical circuits.

What Is Terminal Voltage?

Terminal Voltage refers to the potential difference or electrical voltage measured across the terminals or output terminals of an electrical device, component, or system. In simple terms, it is the voltage available at the output end of a circuit or device that powers external loads.

Factors Affecting Terminal Voltage

Terminal Voltage is influenced by several factors:

  1. Internal Resistance: In practical devices and electrical sources like batteries and generators, there is internal resistance. When current flows through this internal resistance, it causes a voltage drop, affecting the terminal voltage.
  2. Load Resistance: The terminal voltage is also influenced by the load connected to the output terminals. The load’s resistance or impedance determines how much current flows through the circuit, thus affecting the terminal voltage.
  3. Regulation: In regulated power supplies or voltage sources, additional circuitry is used to maintain a constant output voltage, regardless of changes in the load or input conditions.

Calculating Terminal Voltage

The terminal voltage can be calculated using Ohm’s Law, which states that V (voltage) = I (current) × R (resistance). The terminal voltage can be represented as:

Terminal Voltage = E (Electromotive Force) – (I × r)


  • E is the electromotive force or the ideal voltage provided by the source (e.g., battery voltage without internal resistance).
  • I is the current flowing through the circuit or device.
  • r is the internal resistance of the voltage source or device.

Significance Of Terminal Voltage

Terminal Voltage is a crucial parameter in various electrical applications:

  1. Power Distribution: In power systems, the terminal voltage ensures a stable and controlled supply of electricity to homes and industries.
  2. Battery Performance: For portable electronic devices, the terminal voltage of batteries determines how efficiently the devices operate.
  3. Voltage Regulation: In electronic circuits, maintaining a stable terminal voltage is essential for ensuring proper functioning of components.
  4. Electrical Safety: Understanding terminal voltage is crucial for ensuring electrical safety and preventing overloads or excessive voltage in circuits.


Terminal Voltage is the backbone of electrical circuits and systems, providing the driving force for the flow of electricity. Understanding this parameter is essential for engineers, technicians, and anyone working with electrical devices or power systems. By comprehending the factors influencing terminal voltage and how it is calculated, one can design and operate electrical circuits more effectively and ensure the safe and reliable supply of electricity to meet various needs in our modern world. As technology continues to advance, the importance of terminal voltage remains as vital as ever, paving the way for innovations and advancements in the field of electrical engineering.


What Do You Mean By Terminal Voltage?

As the name describes, the terminal voltage is the voltage or potential difference between the positive and the negative terminals of the battery. It is denoted by the letter V and is measured in volts.

What Is Terminal Voltage And Its Formula?

The voltage output of a device is called its terminal voltage V and is given by V=emf−Ir V = emf − I r , where I is the electric current and is positive when flowing away from the positive terminal of the voltage source.

What Is Terminal Voltage Vs Emf?

Recall that the electromotive force is the voltage difference that exists across a battery when electric current does not flow through the battery while the terminal voltage is the actual voltage difference that exists within a battery when electric current does flow through the electric circuit.

What Is Internal Voltage?

The “internal voltage” is the magnitude of the ideal voltage source, which can be closely approximated by the open circuit voltage.

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