TTL of the scheme appeared as result of development of schemes DTL as a result of replacement of a matrix of diodes with the multiemitter transistor. This transistor represents the integrated element uniting properties of diode logical schemes and the transistor amplifier.
As the indicator the seven-segment ALS320B indicator, one of the few indicators capable to display not only digital information, but also alphabetic is chosen that is necessary in the designed device.
Various logical elements total number of 98 names enter the 555th series. Their appointment consists in creation of the COMPUTERS hubs and devices of discrete automatic equipment with high speed and low power consumption.
Value of approximate calculation is more as at its calculation the maximum value of coefficient of failure rate, and in approximate calculation for each element the was taken. Because of this difference in approximate calculation P(t) and Tsr increased.