Controlling a relay with the audio source going to a piezo alarm speaker/sounder SOLVED

I have a basic commerical alsrm system that has a single piezo sounder. There is no other means to output an alarm indication. I need to contrll a relay and have that relay turn on other conventional 12 votl alarm sirens. In the past I have used a simple transistor circut across a regualr speaker input and tha audio source going to the speaker would switch on the relay. I tried connecting this circuit to the piezo speaker. it was able to power on the relay but the volume to he piezo was reduced by 2/3. I know that the a piezo speaker is very different from a regular speaker. Other than that I am at a loss as to how I can accomplish this. Does anyone have a simple circuit that I can construct so that Ican maintain the original volume and still switch on a relay.

by M1871
February 12, 2022

Can you show us (draw the schematic with the built-in editor) the transistor circuit you used before? Without more information, I can only guess, but if your original circuit used a BJT you could build a similar circuit with a MOSFET and get the result you want.

by OakBloodThree
February 23, 2022

1 Answer

Answer by M1871

I do have an drawn mage of the ckt I used but I do not see any means to post it here with this answer. Too much trouble to re-vceate it with the editor. How can I posty an image? Never sen a forum where I can not paste or otherwise post an image.

ACCEPTED +1 vote
by M1871
February 23, 2022

Just to the left of the edit box where you type your answer is a button labeled Add Circuit. This button is also available when you are editing your question.

by OakBloodThree
February 24, 2022

Alternatively, you can find a free image repository, scan your drawing (or sketch), and export it there, then, supply, here, the public url. You probably need to give public access to the image, dependent on your selected image repository.

by vanderghast
February 24, 2022

Sorry for being a little critical on how this form is configured. Just strange how posting/pasting of images, etc, is restricted.

I looked back and found the link to the ckt I referenced in my original post.

Someone mentioned perhaps using a MOSFIT instead of the transistor. I would like to see that concept or any other ideas.

by M1871
February 24, 2022

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.