Hi,

Think I'm going blind.

Goal: make a 555-based buzzer, with piezo/8 Ohm speaker.

Schematics, see attachment, I'm trying to build the one on the right hand side.

When I assemble the parts on a breadboard, it sounds perfect, even with a 8Ohm speaker.

But: When I draw the schematic i KiCad, and make a PCB, it's only coming some strange "hizzzzz" noise. Not what I would expect.

I've nearly spent all Sunday, on this little simple task.

What is the different between my schematic and the one on the right hand side?

I'm open for any ideas and suggestions.

 

Care to show us both sides of the PCB board in a common graphic format?

 

Have you checked if the PCB is fine (tracks, shorts etc)?

 

Here are some pictures, component side and copper side.

I guess I've stared too much at them...

I appreciate tips on placing components for more efficiency.

 

Hi,

I've nearly spent all Sunday, on this little simple task.

What is the different between my schematic and the one on the right hand side?

In your schematic, C2 is connected to the wrong side of R3. C2 should be connected directly to pins 6 and 2 of the 555. You have it connected directly to pin 7.

 

Yep, that is what I'm seeing.

 

You are absolutely right. When I 'quick' soldered the capacitor to the copper side, it's working.

Thanks a lot!

 

I hate that when it happens, but it happens to the best of us.

 

It's good too hear that I'm not the only one, staring and staring at a simple circuit. Without seeing the solution.

Thanks again for the help.