24v relay back up schematic

Dear everyone!

I’m trying to imagine a simple schematic which alternates between a primary and secondary power source via a 24v relay.

The idea is to power up a 24v load (200mA) with a 24v relay which also energize the relay so when primary source goes offline it will switch to secondary 24v source.

Primary source will be a 24v transformer plugged in at the wall and secondary will be a 24v battery bank.

Many thanks,

by Cornelius123
March 22, 2019

1 Answer

Answer by mu34tant

24v double pole double throw relay. put your backup on the normally closed side. when relay is energized by primary the output from the normally open side will power load. when relay is de-energized the output from nc side will power load. put a small diode reverse biased across coil.

+1 vote
by mu34tant
March 30, 2019

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.