I'm new to the arduino world, and I was wondering of there are any restrictions on the speakers you can connect. I plan on building a DAC and I have a 2W 4Ohm speaker i want to use. Will I be able to use this speaker?
Thank you in advance.
Hey welcome, the thing is that Arduino pin can only provide 40 mA which is 0.04A and it won't drive your speaker well, try and you might hear something very very quietly. Build some nice super simple amp, google for TDA7052A which is basically an amp in an IC, or go for LM386 or TL072 simple amps which might work well for you. Don't be afraid to experiment.
And... Per [u]Ohm's Law[/u], 5V/.04 Amps = 125 Ohms. A load of less than 125 Ohms will draw excessive current and that can potentially damage your Arduino. That means you cannot directly connect a normal 4 or 8 Ohm speaker.
DAC chips don't generally directly drive speakers either.
However, you can connect powered computer speakers. The speakers themselves may be 4 or 8 Ohms, but the amplifier has much higher input impedance.