This circuit is a fun light-project where you have 10 lights “running” along a line.
Pin 3 of the 555 timer has a voltage that goes on and off repeatedly. This signal is connected into pin 14 of the 4017 IC.
The 4017 IC counts each time the voltage on pin 14 goes from low to high. It has 10 outputs that represent how many times the voltage has gone from low to high (0 to 9). For example, after 3 counts, output Q3 goes high, while the others are low. On the 10th count, the counter starts from 0 again.
The running speed is set by R1, R2, and C1. Change one of the values, and the running speed of the lights will change.
Here’s the pinout for the 4017 IC:
And here’s a video of the circuit I built:
The Circuit Diagram
Find the components used in the table below. Click here to buy the complete kit.
|R1, R2||10 kΩ||Two standard resistors|
|C1||4.7 μF||Polarized capacitor|
|L1 to L10||LED||Standard light-emitting diode|
|U1||NE555||555 Timer IC|
|U2||CD4017B||4017 Decade Counter|
Are You Stuck?
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