Piezo Buzzer quieter using external power than using usb (both 5V)?

[allinonemovie]

I have the following circuit:

When I power the arduino using the USB-Port, everything works as expected. If I use the VIN- and Ground-Pin however (using 5V as well), the Piezo Buzzer is much quieter. Does anybody know why? Electronics noob here

[Coding Badly]

Are you applying 5V to VIN / GND?

[allinonemovie]

using 5V as well

[Coding Badly]

It would have taken less effort to directly answer my question politely asking for clarification.  If you can't be bothered to type "yes" or "no" then I can't be bothered to help you.

Good luck with your project.

[allinonemovie]

Sorry if that was unfriendly, it wasn't meant like that. I just thought if someone skims through this post, a quote highlights it once again (because you can easily miss it in the post, just like you did).

To make it even more clear, I added it to the title as well.

[Coding Badly]

I apologize for the misunderstanding.

Do you have a volt meter / multimeter?

[allinonemovie]

Yes, I measured GND against VIN to be approximatily 5V in both cases. The current of the power supply isn't limited and the voltage doesn't drop. It's hard to measure the voltage between D7 and ground when audio is playing, because it's changing so quickly, that my multimeter isn't able to give decent results. Sadly I don't have an oscilloscope

[Coding Badly]

Measure VCC to GND while powering through VIN.

[PieterP]

Vin goes through an LDO, the minimum recommended voltage is usually between 6 and 7V. If you have clean, regulated 5V DC, you can feed it into the 5V pin.

Pieter

[TomGeorge]

Vin goes through an LDO, the minimum recommended voltage is usually between 6 and 7V. If you have clean, regulated 5V DC, you can feed it into the 5V pin.

Pieter

Exactly, Vin is before the 5V linear regulator, it needs 7V or more on Vin to give regulated 5V supply.

• If you measure the 5V pin with 5V connected to Vin, you will see it is less than 5V.
• If you measure the 5V pin with 7V to 12V connected to Vin, you will see it is 5V.

Tom...  

[allinonemovie]

Thank you! That explains the issue. Interestingly the issue disappeared after soldering, so it seems that there was another problem, but luckily sometimes issues fix themselfs But that's good to know for future projects!