A light-emitting diode is a semiconductor component that emits light when an electric current flows through it in the forward direction. Around 1962, LEDs were used as illuminated displays and at the end of the 1990s, due to technological developments and higher luminous efficacy as well as the generation of white light, were also relevant as illuminants for everyday lighting. The miniaturization of LEDs from the classic 5mm and 3mm versions to SMD LEDs is also ideal for use in the illumination of LEGO Models.
So-called LUGs are clubs which are registered as such with the LEGO Group. There is a (limited) mutual exchange of information between LUG and LEGO through an ambassador, who must meet certain requirements on the part of the LEGO Group.
R is usually used as the symbol for the electrical resistance. It is derived from the Latin resistere for "resist".
The fastening elements on the outside of a clamping module are known as "knobs". With LEGO, the lettering is usually embossed on each knob and thus represents an important identification feature of a genuine LEGO element. A pimple is 1.7mm high and has a diameter of 4.8mm.