What is BS EN 60063 - Preferred number series for resistors and capacitors about?  
BS EN 60063 is an international standard that discusses number series for resistors and capacitors.
BS EN 60063 provides a series of preferred values for the resistance of resistors and for the capacitance of capacitors.
BS EN 60063 specifies technicalities such as related terms and definitions, number series, application of an E series, etc.
The definition of such series with a defined numeric resolution is a basic prerequisite for the marking and coding of capacitors and resistors with their respective capacitance or resistance values as described in IEC 60062.
Who is BS EN 60063 - Preferred number series for resistors and capacitors for? 
BS EN 60063 on preferred number series for resistors and capacitors is useful for: 
- Designers of capacitors and resistors
- Manufacturers and suppliers of capacitors
- Manufacturers and suppliers of resistors
- Quality control personnel
- Electronics equipment manufacturers
Why should you use BS EN 60063 - Preferred number series for resistors and capacitors?  
Like any other passive electronic components, capacitors and resistors come with standard values. These values are centred on a geometric series which is also known as the E series. E series are infinite series of numeric values with a given number of elements per decade, rounded, or derived from the elements of a geometric series.
BS EN 60063 provides you with the marking and coding systems that are useful for indicating the value and the tolerance of the resistors, the capacitors, and other electrical components. It enables the manufacturers to obtain the marking system depending upon the availability of space, and according to the capacity of resistors and capacitors.
BS EN 60063 presents information about establishing a marking system that is in compliance with international standards, in order to avoid any confusion or chaos regarding the value and practicability of the resistors and the capacitors.
What’s changed since the last update?
BS EN 60063:2015 supersedes BS 2488:1966, which is withdrawn. BS EN 60063:2015 includes some technical changes with respect to BS 2488:1966. These include: 
- Revision of the information on a relationship between an E Series and the tolerance of resistance or capacitance value of a respective component
- Introduction of advice on a possible deduction from the marking of a component to an associated E Series and also to an associated tolerance
- Complete editorial revision 
