This is a small size led flasher built with the 555 timer IC that is powered from 2 x 1.5V batteries. The circuit can be used as a flashing metronome, dark room timer, memo-reminder or other similar ...

The project is aimed at Arduino-based circuits, but any chip with an ADC will work. The 555 timer is used as a free running oscillator.

Let’s Look at the Schematic In a PWM circuit, the 555 timer will output a logic signal “high” and “low” depending on a ratio derived by the value of a few components connected.