Analysis of information sources in references of the Wikipedia article "555 timer IC" in English language version.
The 555 timer chip, developed in 1970, is probably the most popular integrated circuit ever made. By some estimates, more than a billion of them are manufactured every year.
The 555 gets its name from the three 5-kW +VCC R1 discharging path 555 R 2 C 6 resistors shown in the block diagram. These resistors act as a three-step voltage.
The 555 got its name from the three 5-kOhm resistors
The reference voltage for the comparators is established by a voltage divider consisting of three 5 - k2 resistors, which is where the name 555 is derived
Not all functions are brought out to the 558's pins. This chip is designed primarily for monostable multivibrator applications
