Sequential Logic

I am trying to make a traffic light and having a bit of trouble gating the circuit to change states. Is there something I am missing. Please help.

by s3665153
September 09, 2018

Try using a 555 timer and a 4017 counter followed by diode logic to get the four states, 1234 red 5 red amber 6789 green 10 amber,

by mikerogerswsm
September 09, 2018

I am hoping to only make use of D flip flops.

by s3665153
September 09, 2018

Impossible - you will need first to generate a clock!

by mikerogerswsm
September 09, 2018

If you look at a 4017 datasheet you will see a Johnson twisted ring of five D flip flops and some logic gates. You will need some glue logic instead of diodes to detect the 1234, 5, 6789 and 10 states. Also some lamp drivers. End. mike

by mikerogerswsm
September 10, 2018

Thanks will do.

by s3665153
September 11, 2018

No Answers

No answers yet. Contribute your answer below!


Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account


Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers


Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.


About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.