The function of the 555 timer is mainly determined by two comparators. The output voltage of the them controls the state of the RS flip-flop and the discharge tube. It also contains 3 working states.

The 74LVC14A is a low-power hex Schmitt trigger with inverting buffers that can be driven from either 3.3 V or 5 V devices. It is generally used as wave and pulse shapers for high noise environments ...

More undocumented applications for the 555 ‘oscillator:’ Not all applications oscillate as we will see. Most are knowledgeable about common CMOS logic inverters and Schmitt triggers such as the 74HC04 ...

This application note presents the need to use an external Pierce oscillator to replace the RTC oscillator circuit that makes EP93xx susceptible to on-chip noises. It describes the implementation of ...