LM317T Voltage Regulator with Pass Transistor

4 leds, light up one after another, from left to right, one at a time. Components used: external power supply connected to 5V voltage regulator IC "7805", "555" timer IC, stadart logic IC's -- "74253" (8 D-type flip-flops), "7408" (AND gate) and "7404" (NOT gate), 5 leds (one is connected directly to the timers output, to make the clock signal visible), a few resistors and capacitors.



http://www.youtube.com/watch?v=-pS0JrSZ1JI&hl=en