This circuit uses a 555 timer which is setup to both runn in an Astable
operating mode. This generates a continuous output via Pin 3 in the
form of a square wave. When the timer's output changes to a high state
this triggers the a cycle on the 4017 4017 decade counter telling it to
output the next sequential output high. The outputs of the 4017 are
connected to the LEDs turning them on and off.
Schematic
Parts List
1x - NE555 Bipolar Timer
1x - 4017 Decoded Decade
6x - 1N4148 Diode
1x - 1K Resistor (1/4W)
1x - 22K Resistor (1/4W)
2x - 4.7K Resistor (1/4W)
6x - 470 Resistor (1/4W)
1x - 2.2µF Electrolytic Capacitor (16V)
2x - BC547 NPN Transistor
2x - LED (Blue)
2x - LED (Red)