user5103: I know little about electronics in general. I wanted to connect Arduino, and play a tone using tone() through my home speakers.
I've used a 1/8'' audio jack and connect ground to ground and left/right to pin 2. Run it and it was too loud.
Then I read the specification and it says,
Input impedance = 20 kOhm 
Input sensibility = 400mV +/- 50mV
Arduino sends 5V so that should be a lot. Did I damage my speaker? They still work.

user368: It's probably not damaged, but you shouldn't do it again.
To get the 5V signal down to 400mV you need to create a voltage divider. As such you will need a:
5V / (400mV / 20kohm) − 20kohm = 230kohm
resistor between the pin and the input. 220kohm should be close enough.

5103: <p>I know little about electronics in general. I wanted to connect Arduino, and play a tone using tone() through my home speakers.</p>

<p>I've used a 1/8'' audio jack and connect ground to ground and left/right to pin 2. Run it and it was too loud.</p>

<p>Then I read the specification and it says,</p>

<p>Input impedance = 20 kOhm </p>

<p>Input sensibility = 400mV +/- 50mV</p>

<p>Arduino sends 5V so that should be a lot. Did I damage my speaker? They still work.</p>
 368: <p>It's probably not damaged, but you shouldn't do it again.</p>

<p>To get the 5V signal down to 400mV you need to create a voltage divider. As such you will need a:</p>

<p>5V / (400mV / 20kohm) − 20kohm = 230kohm</p>

<p>resistor between the pin and the input. 220kohm should be close enough.</p>
