Hello! I have an Arduino micro that is connected to a 5v speaker and is also powering it + some LEDs. the only power supply is going straight to the Arduino, so the speaker is also powered by the Arduino. I have noticed that if I power the Arduino with the USB from my computer then the speaker is much louder than if the Arduino was powered by a 9/12v battery. Doesn't the USB output 5v, so why is this happening? I want to know so I can get the speaker to the same volume while using the battery.
The difference is the current capabilities of the 2 power sources. Power is voltage * current so both have to be adequate for the project to work. If you are powering using a 9V to 12V battery you are probably connecting through the power plug or Vin. Those connections go to the onboard 5V regulator. That regulator is not heat sinked so it can supply limited current before it starts to heat up. With a 12V input the onboard regulator can only supply about 150mA. USB on the other hand can supply 500mA.
Then the batteries themselves may have limitations. 9V smoke alarm batteries, for instance, have very little current capability and so have little use with Arduino projects.
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In that case, would a 5V 500mA lipo battery be able to give the same power output as the USB?
Are you using an UNO?
no a Micro
If you connect the USB to a power bank or a 5V USB charger it should be the same loudness.
Yes it is but I need something more compact
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