This symbol stands for Denmark's DEMKO certification. DEMKO is an independent company founded in 1928 by the Danish government to test product safety. Its task is similar to that of Germany's TÜV: DEMKO inspects electronic products for safety and awards the corresponding symbol where the proper requirements are met.


A computer's CPU is the complete primary processor. The DIE by contrast is a processor’s most important semiconductor, since the transistors for signal processing are placed on it. The CPU can be described as a carrier board for the DIE. A modern DIE is produced to 32 nanometres, corresponding to several hundred million transistors on 1cm2.

Dual Rail

A dual rail is a 12V power supply voltage divided between two sub-rails. During the splitting of the individual voltage rails, the voltage remains at 12V, although the current is divided between the two sub-rails.


DC-DC (direct current to direct current) is an innovative technology used by power supply manufacturers. Conventional power supplies use a transformer to generate the 3.3V, 5V and 12V current. With DC-DC technology, only the 12V current need be generated in the transformer. Potential transformers are used to create the other two voltage rails.


DARK POWER PRO power supplies from be quiet! represent high-powered hardware components with whisper-silent operation and optimal cooling of the system. The high-end power supplies feature cable management and come with optional 12V multi-rail or single-rail operation. These are especially suited for HD gaming and multimedia, server-based multi-GPU systems, 3D CAD graphics, photo editing and video editing applications.

DC (Output)

The acronym stands for "Direct Current". Direct current is electricity that does not change its direction (positive or negative).


dB(A) is used as a measurement of sound pressure levels. The capital A in parenthesis indicates that the sound pressure is measured with a filter in front of the measuring device to replicate the sensitivity of the human ear. In technical usage, manufacturers indicate volume in dB(A).