555 Timer Astable Flashing LED

This circuit uses the 555 timer in an Astable operating mode which generates a continuous output via Pin OUT in the form of a square wave. This turns the LED on and off. The speed at which the LED is turned on and off is set by the values of R1 and R2. The blink frequency can be calculated using this formula: 1.44/((R1+2R2)C1).