3 Switches circuit

Hello I am a graphic designer and not really good at electronics but for a project I have to make a circuit. I thought maybe you could help me. Sorry if the question is dumb.

I have 3 switches. Each of them are attached to a lamp (Red, Blue, and Green). I want at least 2 lamps to be always ON. For example, all of them are ON. We push the blue one off. Then if we push the red one off, the blue one gets on automatically. Therefore, the circuit do not let less than one lamp to be off. Thank you so much and I hope it was clear. Cheers

by sinasina
September 19, 2018

I would suggest a ring of three relays, with contacts interconnected so that only one can be on at a time. Arrange them to turn a light on when off. Make your buttons break the supply to each.

by mikerogerswsm
September 19, 2018


by mikerogerswsm
September 19, 2018

Minor edit 'break' should read ' make'.

by mikerogerswsm
September 19, 2018

Full circuit now shown.

by mikerogerswsm
September 19, 2018

1 Answer

Answer by mikerogerswsm


Opens as pdf, use print/export button.

Suitable relay 4 for ten quid:


Suitable power: 4 x AA cell in series.

If you use leds put 220 ohms in series with each one to limit the current.

+1 vote
by mikerogerswsm
September 20, 2018

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.