Teholähde

Teholähde is a term used in Finnish to denote a source that provides electrical power to a circuit or system. In technical contexts it is often used as a general synonym for power source, distinguishing the origin of energy from the load. The word combines teho, meaning power or throughput, with lähde, meaning source. The term appears in physics and electrical engineering literature as well as in energy policy and industrial terminology to describe devices or systems that supply usable electrical energy, such as a battery, a power adapter, a generator, or a renewable energy installation.

In circuit theory, teholähde may be treated as an idealized source with fixed output characteristics, and it can be modeled with internal resistance in real-world applications. Real teholähteitä have limitations in voltage, current, regulation, and efficiency, and they are described by output specifications such as open-circuit voltage, short-circuit current, and internal impedance. The concept helps distinguish power sources from passive loads and other components in a circuit.

Common usage spans electronics, electrical engineering, and energy systems. In schematics and design work, teholähde denotes the origin of electrical power for a subsystem. In energy planning and policy discussions, it refers to sources of energy supply, including various technologies and fuels, depending on context. The term is neutral and versatile, with more precise terms such as jännitelähde (voltage source) or, in some contexts, virtalähde (current source) used when specificity is required.