Feszültségforrásként

Feszültségforrásként (literally “as a voltage source”) is a term used in electrical engineering to describe any device or element that provides a voltage difference across its terminals. The concept is central to circuit analysis, as voltage sources are the primary means of driving electric current through a network.

An ideal voltage source is defined by two properties: it maintains a fixed voltage regardless of the current drawn from it, and it provides zero internal resistance. Real sources, such as batteries, electrochemical cells, photovoltaic cells, or signal generators, deviate from this ideal behavior. They possess an internal resistance that causes the output voltage to drop with increasing load current, a phenomenon described by Thévenin’s theorem. The internal resistance is typically referred to as the source’s equivalent resistance.

Voltage sources are classified by their method of operation. Electrochemical cells produce electromotive force through chemical reactions, while photovoltaic cells convert light into electrical energy. Transistor-based voltage regulators and switching power supplies provide stable voltages by dynamic feedback control. Signal generators, such as function generators, supply time-varying waveforms and are employed in testing and measurement.

In circuit theory, voltage sources are represented by a voltage label V placed in series with an internal resistor. Kirchhoff’s voltage law is applied by summing the voltages around a loop, treating the source contribution as its specified voltage. The superposition principle allows the analysis of circuits with multiple independent voltage sources by considering each source separately while replacing the others with short circuits.

Typical applications of feszültségforrásként include powering electronic devices, maintaining consistent operating points in analog circuits, and providing reference voltages for precision measurements. In power distribution, high‑voltage sources feed transmission lines, whereas low‑voltage sources (such as battery packs) are used in portable equipment. Understanding the characteristics of a voltage source—its internal resistance, supply voltage stability, and maximum output current—is essential for designing reliable and efficient electrical systems.