Count To Ten With Lights

The circuit presented this month is a basic configuration of the very versatile 4017 IC Chip. In the most common use of the IC, it will turn on 10 separate outputs sequentially. Typically, the circuit is used to turn on a LED for certain time cycle. In the circuit shown the VR can be adjusted so that the clock output of the NAND gate will be 1 second. With this clock at 1 second intervals, the 4017 chip will turn on output # 0 to be high which will light and LED. When clock pulse 2 is received a second later, output #1 will go high which will turn on LED2. This process will continue until all 10 outputs have gone on and then it will start all over again until you turn the power off. When building this circuit you should tie the left over pins of the other NAND gates in the CD4093 to ground. Therefore, pins 5,6,8,9, 12 and 13 should be connected to ground.

From : http://home.maine.rr.com/randylinscott/jun21.htm