this is a flasher ie for turning signal. just press the switch for left or right. for 12v(13,5) automotive battery this can handle up to 5 leds. adjust the brightness with the 10k trimpot. the pnp bjt is a multy purpose switching that can handle at least 50v e-c. the npn is up to you to choose the rate of amplification (hf) with 50v c-e. a simple 2n2218 can do the job.
