Lexikon Leistung specifications

Category : Lexicon

The power is a physical quantity that indicates how much energy is converted or transmitted per unit of time. The unit of measurement is the watt.

The electrical power at a load results from the product of a current flowing through a load with the voltage dropping across the load. In most cases, the energy delivered to the load in this way is ultimately largely converted into heat. In the case of an electric heater, this is the only purpose, and the amount of heat generated per unit of time results from the power indication of the heater in watts.

Other electrical devices convert only a part of the absorbed power into heat, the rest is released in a different way. For example, an electric motor emits a part of the absorbed electrical power back as mechanical power. A radio transmitter emits the recorded electrical power partly in the form of electromagnetic waves. In such cases, the heat emitted is usually an undesirable by-product, which corresponds to a loss of energy. One therefore speaks of the power dissipation in this heat generation. The ratio between the power output in the desired form and the power absorbed from the power grid is called the efficiency of the device, which is often indicated as a percentage.

In the Hi-Fi sector, performance is of particular interest for loudspeakers and power amplifiers. Here, the amplifier is supposed to supply the energy that the speaker then converts into sound.

The actual power output by an amplifier depends on the type of sound signals being played and their desired volume. Normally, this is far below the power specifications of amplifiers or loudspeakers. For room volume, a power of well below one watt is required for most speakers. The power specifications of loudspeakers and amplifiers therefore relate more to theoretical limit cases, which are determined with the help of measurement signals.