 Why is the triple-five timer one of the best-known ICs of all time? Well, it's been around a long time and there's a crazy amount of example circuits out there for it It's also cheap easy to use and most of all versatile a 555 timer can be used as a timer performing a single action after a specific period of time an Oscillator generating a repeating waveform at a specific frequency a PWM signal generator Outputting a waveform of varying pulse width for controlling servo motors leds Etc. Plus less practical uses like using two of them together to create a stepped tone generator a ka tarry punk console For a modern update to the 555 consider the TLC 551 It's pin compatible with the original has a wider input voltage and higher accuracy