Abstract
The paper deals with determining the final value of simple systems reliability. Simple systems, the systems with simple interconnections, can be divided into a sequence of series and/or parallel subsystems. The paper presents the basic functional relationships used to assess the reliability of simple systems, however, they are also essential for understanding more complex systems. The paper graphically shows and analyzes the final reliability of the systems depending on the arrangement of subsystems, and also those depending on the number of subsystems.