BeginnerLighting
Ten-Step LED Chaser
Pair a 555 clock with the CD4017 counter to move one lit LED through ten outputs.
Parts from the database
Other supplies
- breadboardCommon build supply
- regulated 5 V supplyCommon build supply
- ten LEDsCommon build supply
- ten 1 kΩ resistorsCommon build supply
- 10 kΩ resistorCommon build supply
- 100 kΩ potentiometerCommon build supply
- 10 µF electrolyticCommon build supply
- 100 nF bypass capacitors ×2Common build supply
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Connections
- Wire the NE555 astable: pins 1/8 to ground/+5 V, pin 4 high, pins 2/6 joined, 10 kΩ from +5 V to pin 7, 100 kΩ pot between pin 7 and pins 2/6, 10 µF from pins 2/6 to ground (+ at node). Pin 3 is clock.
- CD4017: pin 16 +5 V, pin 8 ground, pin 14 to 555 pin 3, pin 13 low, pin 15 low. Bypass pin 16 to pin 8.
- Wire Q0–Q9 at pins 3,2,4,7,10,1,5,6,9,11, each through its own 1 kΩ and LED to ground. Bypass the 555 too.
Build steps
- Test the 555 clock first.
- Add the 4017 and confirm its DIP orientation.
- Add one LED at a time using the listed output order.
- Turn the pot to change the sequence speed.
Software and firmware setup
This is a hardware-only circuit; no firmware is required.
Test your build
Exactly one LED should be on at a time and advance on each rising clock edge.
Troubleshooting
- All dark: check pin 13 low, pin 15 low, and clock at pin 14.
- Skipped steps: shorten clock wire and add bypass caps close to both ICs.
- Dim LEDs: verify polarity and use an individual resistor per LED.
Safety and limitations
Use 5 V and do not connect relay coils or motors directly to 4017 outputs.
Manufacturer and platform documentation
Community Notes for This Project
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