The common term “electrical pressure” is used to describe electrical potential difference, which is more formally known as voltage. This concept represents the force or push that drives electric charge through a conductor, similar to how mechanical pressure drives fluid flow. To answer the immediate question, electrical pressure is measured in Volts. This unit quantifies the energy available to move a unit of electrical charge from one point to another within an electric field.
The Standard Unit of Measurement
The standard international unit (SI unit) for electrical potential difference is the Volt (V). This unit is named in honor of the Italian physicist Alessandro Volta, who invented the voltaic pile—the first true electrical battery capable of providing a continuous electric current.
A single Volt is defined as the potential difference between two points of a conducting wire when an electric current of one ampere dissipates one watt of power. This definition links the electrical pressure directly to the concepts of power and current flow within a system.
Potential Difference Explained
Potential difference is the underlying scientific concept that the term electrical pressure simplifies. It describes the difference in electrical potential energy between two points in a circuit, providing the motive force required to push electrons and establish an electric current.
To visualize this concept, the analogy of water pressure in a pipe system is often used. Voltage is analogous to the mechanical pressure that pushes water through a hose; a higher voltage drives a greater current, similar to how a high reservoir creates a stronger flow.
Voltage is formally defined as the amount of potential energy per unit electric charge. One Volt is equal to one Joule of energy per one Coulomb of charge, demonstrating the work required to move the charge.
Voltage in the Electrical Circuit
In a practical circuit setting, voltage is measured using a device called a voltmeter. Unlike devices that measure current, the voltmeter must be connected in parallel across the specific component or section of the circuit where the potential difference is determined. This parallel connection ensures the voltmeter measures the energy drop across the component rather than the flow through it.
The magnitude of this electrical pressure directly influences the flow of charge, or current, within the circuit. Current is measured in Amperes, and the opposition to this flow, known as electrical resistance, is measured in Ohms.
The relationship between these three quantities—voltage, current, and resistance—is described by Ohm’s Law. This equation states that voltage (V) is equal to the current (I) multiplied by the resistance (R), written as V=IR. For a fixed resistance, increasing the electrical pressure results in a proportionate increase in the electrical current.