Georgia said...Hi,I am running a little 8 ohm speaker with the transistor as you suggested. It works great but it is getting quite hot. Do you have this problem?January 20, 2013 at 7:17 PM
If its getting hot, it has a lot of current going thru it.With a speaker in series, that's like having an 8 ohm resistor from +5 to Gnd.With some voltage drop across the transistor, you could have something like 500mA going from Collector to emitter.Is 2N706 the correct P/N? Like this?http://www.abra-electronics.com/products/2N706-Transistor-General-Purpose-NPN-10mA-20V.htmlhttp://www.digchip.com/datasheets/parts/datasheet/417/2N706A-pdf.phpThat part is only rated for 10mA. You're gonna smoke it.A one transistor amplifier will work much better like thishttp://electroschematics.com/6910/single-transistor-amplifier-revisited-part-1/or herehttp://www.fastquake.com/2012/02/simple-transistor-amplifier-circuit-schematic-and-explanation/taking your output from the right of C3.