This little circuit provides a surprisingly spectacular bright strobe flash which is adjustable with P1, the 200K trimmer potentiometer. P1, R1, R2, and C1 provide the flashrate. R1 sets the upper flashrate. The flashrate for the above circuit was measured at 12Vdc. If the supply voltage is steady or regulated, the flashrate is very stable. Capacitor C2 on pin 5 of the IC is to filter off noise when used in motorized vehicles. For battery power it can be eliminated. Resistor R3, 47 Ohm, is there to protect the Leds for burn-out. Depending on your application and power source, increase or decrease the value of R3. Like, for a 9V power source decrease the value to 22-33 ohms or so. For a 15V power sourse increase the value to 680-1000 ohms. Circuit Diagram: The duty-cycle is about perfect at 50% so will give a nice strobe when adjusted with P1 to a fast flash. I experimented with several color Leds and basically they all strobe very bright especially the white ones. Current draw of this ...