All electrical elements are grouped in rational units, a feature 
uhich makes servicing and trouble-shooting much easier, 
although it may be said that the operational reliability of the 
E4 is high. As far as possible, hermetically sealed elements 
have been used in the circuits to reduce atmospheric influences 
to a minimum. Since, as is knoun, the characteristics of semi 
conductors can change gradually with time, the circuitry has 
been designed in such a way that even larger deviations from 
the original properties will not cause defects. Lastly, the 
generous dimensioning of the circuitry and careful choice of 
all components contribute towards increasing the reliability 
and operational life of all electrical and electronic control 
elements.