Ohmic consumer
A resistive consumer is a consumer of energy that fulfills two properties at the same time:
- It behaves like an electrical consumer .
- It behaves like an ohmic resistor .
Electrical consumers can convert electrical energy into other forms of energy or other forms of electrical energy and derive a direct or indirect benefit from it. The energy is usually transported from the source to the consumer via a line and is then expressed as an electric current at an electric voltage .
The simplest model of a consumer behaves according to Ohm's law , according to which voltage and current strength are proportional to each other at every instantaneous value . This model is called "ohmic resistance". Its mathematical treatment is the simplest compared to the consumers listed below. It is therefore advisable to often check to what extent a consumer can be treated approximately as an ohmic resistance.
Ohmic-inductive and ohmic-capacitive loads behave like an impedance . For stationary processes there is also proportionality between voltage and current strength, but only for RMS values and amplitudes of sinusoidal quantities. Because of the phase shift , the proportionality does not apply to instantaneous values. - Consumers that are supplied from the mains and contain rectifiers or power supplies usually have a sinusoidal voltage. In contrast, the current intensity shows a different curve (except for power factor correction filtering ). These and other non-linear consumers do not meet the requirement for an ohmic resistance.
Individual evidence
- ↑ EN 80000-6, Quantities and Units - Part 6: Electromagnetism , 2008; Entry 6-46.
- ↑ IEC 60050, see DKE German Commission for Electrical, Electronic and Information Technologies in DIN and VDE: Internationales Electrotechnical Dictionary - IEV. Entry 131-12-04