This is an Astable or a free running pulse generator. R4.7k and R10k and capacitor 10 uf controls timing and duration of flashes. R1k limits current to led to reduce 470 homs for brighter flashes. With a cap 100uf conect ed across the cap 10 uf the flashes delay for 2 seconds. See how it works without any capacitor using the switch.
