How to Design a voltage change detector circuit

Help with designing a universal voltage change detector.

The input voltage as well as the Pull up resistor could be differential.

Basically i want to output a digital signal when the voltage drops 0.5 volt regardless of the input voltage.

Eg.. V drops from 14 to 13.5 output=1

by Eng_Roy
December 06, 2019

1 Answer

Answer by Chamsta

Hi Eng_Roy,

My best attempt at solving your problem wouldn't result in a universal 'plug and play' circuit, but one which could be adapted to the circuit in which it is being placed.

I would suggest a comparator with a 10k resistor and a 10k trimmer potentiometer, allowing you to put the detector in place, and fine tune it to output the value '1' based off a percentage of the max value being input to the comparator.

It maybe isn't perfect in terms of what you are looking for, but it certainly is one way to go about it without knowing any more constraints.

Hope this helps, Chris.

+1 vote
by Chamsta
December 10, 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.