2 npn transistors and 2 capacitors. One of the capactiors starts charging while it is charging it triggers the transistors in the other side so the led on the other side opens after it charges it self it the current flows to the collector of the transistor and the other capacitor will have been charged by then and it triggers the other transistors base. It goes on on . You can change the time by adjusting the value in the capacots. For example if you set the value to 100 piko fahrat then it starts flipping in every 2 seconds.
