BeginnerDisplays & Logic
Manual 8-Bit Shift-Register Display
Load a pattern one bit at a time into an SN74HC595 and display its eight stored bits with LEDs.
Parts from the database
- SN74HC595N × 1Serial-to-parallel register
Other supplies
- breadboardCommon build supply
- 5 V supplyCommon build supply
- two pushbuttonsCommon build supply
- two 10 kΩ clock pull-upsCommon build supply
- data switch and 10 kΩ pull-downCommon build supply
- eight LEDsCommon build supply
- eight 1 kΩ resistorsCommon build supply
- 100 nF bypass capacitorCommon build supply
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Connections
- Pin 16 +5 V, pin 8 ground, pin 10 (/SRCLR) high, pin 13 (/OE) low; bypass pins 16/8.
- Data to pin 14, shift clock pin 11, storage clock pin 12. Give each clock input a 10 kΩ pull-up and button to ground; data has a pull-down and switch to +5 V.
- Connect QA–QH (pins 15,1,2,3,4,5,6,7) through individual 1 kΩ resistors and LEDs to ground. Leave pin 9 open.
Build steps
- Set data high or low and tap shift clock once.
- Repeat eight times; later bits shift earlier bits along.
- Tap latch clock to copy the pattern to LEDs.
- Try alternating and grouped patterns; button bounce can create extra edges.
Software and firmware setup
This is a hardware-only circuit; no firmware is required.
Test your build
LEDs show the last eight shifted bits after the latch clock. This is a manual logic demonstration, not a debounced controller.
Troubleshooting
- No LEDs: pin 13 must be low and pin 10 high.
- Bits shift unexpectedly: press buttons slowly; contact bounce can add clocks.
- Only some outputs work: check QA–QH pin order and LED resistors.
Safety and limitations
Use 5 V and individual LED resistors; do not connect outputs directly to relays or LED strips.
Manufacturer and platform documentation
Community Notes for This Project
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