elementcollector1 Posted May 21, 2012 Share Posted May 21, 2012 I have an 8-ohm, 0.5 watt speaker that is the perfect size for a project I am attempting. Is it possible to hook this up to an mp3, ipod, or Arduino Uno? Link to comment Share on other sites More sharing options...
Externet Posted May 21, 2012 Share Posted May 21, 2012 Yes, it is possible, feed it a signal not exceeding about a volt RMS AC, the source device should be capable of handling a low impedance load. Link to comment Share on other sites More sharing options...
elementcollector1 Posted May 21, 2012 Author Share Posted May 21, 2012 How much voltage do mp3's put out? Link to comment Share on other sites More sharing options...
Externet Posted May 21, 2012 Share Posted May 21, 2012 Just measure it with an AC voltmeter or oscilloscope at the volume setting you want, with the load (speaker) connected on one channel. There may be dozens of different players with different output designs to answer your last question. Link to comment Share on other sites More sharing options...
elementcollector1 Posted May 21, 2012 Author Share Posted May 21, 2012 Ha...sorry, what? I'm not much of an electronics hobbyist yet... Link to comment Share on other sites More sharing options...
Xittenn Posted May 21, 2012 Share Posted May 21, 2012 8 ohms is a nominal impedance @1khz. If you drive it down to 100hz your impedance will drop to 0.8 ohms impedance. Most portable listening devices output somewhere between 1 and 2 volts and are designed to drive loads around 16 - 32 ohms nominal impedance @1khz. Assuming that your portable listening device is capable of a clean .05 watts @ 1 volt you get ~.05 amps @ 16 ohms nominal impedance. Your 8 ohm speaker will probably have a much more linear range than headphones and you will be driving your device well outside of specification if you open it up completely. It's not that it won't drive it, it's just that you will shorten the life of your listening device! Link to comment Share on other sites More sharing options...
elementcollector1 Posted May 22, 2012 Author Share Posted May 22, 2012 Can I put something in between the two to control the impedance? I'll try to see how many amps / volts my ipod puts out. Link to comment Share on other sites More sharing options...
doG Posted May 22, 2012 Share Posted May 22, 2012 Can I put something in between the two to control the impedance? I'll try to see how many amps / volts my ipod puts out. An audio taper potentiometer will work. Link to comment Share on other sites More sharing options...
Joatmon Posted May 22, 2012 Share Posted May 22, 2012 (edited) What is described is a need for impedance matching. Two common methods are (a) using a transformer. Which provides efficient transfer of power without being able to add power. http://nuclearpowert.../h1011v4_46.htm or (b) using a transistor as an emitter follower. As well as providing efficient transfer of power, this can add power as it amplifies current. (taken from the transistor supply) http://www.carlomoze...iles/Unit_4.pdf Edited May 22, 2012 by Joatmon Link to comment Share on other sites More sharing options...
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