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How to Build an LED Chaser Circuit

An LED chaser circuit is a common, eye-pleasing use for LED lights. This type of circuit consists of a row of LEDs that blink in sequence and then repeat. Special integrated circuits, or IC, microchips control the sequencing of the blinking. An electronics hobbyist can pick up the appropriate ICs and most of the other required parts at local electronics hobby shops for less than $2 each.

Things You'll Need

One M-Ohm 1/4W resistor
100K Potentiometer
1K-Ohm 1/4W resistor (220 Ohm if using blue LEDs)
0.1uF 16V Ceramic disk capacitor
4011 CMOS NAND gate IC
4017 CMOS counter IC
10 LEDs of any color
Printed circuit board
Jumper leads
9-volt power supply

Instructions

- 1
  Insert one end of the one mega-Ohm resistor into the PCB so that it connects to the two input nodes of the 4011 CMOS NAND gate IC. Insert one end of the capacitor at the output terminal of the IC. Connect one end of the potentiometer at node three of the IC.
- 2
  Connect the other end of all three components from the previous step to each other in a common row in the PCB. Power the IC from node 14 with the 9-volt power supply.
- 3
  Power the 4017 CMOS counter at its node 16 with the 9-volt power supply as well. Link the IC to the first IC by jumping a lead from the output of the first IC to node 14 of the CMOS counter.
- 4
  Connect nodes 15, 8 and 13 on the 4017 CMOS counter to ground. Connect the 10 LEDs to all 10 nodes on the output side of the IC. Finish by grounding the other ends of the LEDs through the one kilo-Ohm resistor.

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