Speaker for Stamp 2

jpyle

I have a question about the correct speaker to use for output from the Stamp2. directly powered by the Stamp.. I have been using an 8 Ohm .25 Watt , with very low volume. I have a 10 uF cap inline with input. Works fine, low volume, but works good. Problem is that I have a 50 Ohm, at .1 tenth watt, and I have NO idea as how to use this on the Stamp ,without doing damage to either. The impedence matching is above my head. Can anyone give me a clue as how to use this .1 Watt speaker on the Stamp?? Thanks in advance! John (I am using dual tone generation on the stamp--DTMF---Playing with frequency output, and would like to hear the results.) I am a "Hands On" type of guy---Or "Ears On " in this instance!!!

Leon

You can't drive a loudspeaker from a PIC output! You need an amplifier of some sort.

You could connect a piezo element directly to the Stamp, of course, if you just want it beeping.

Mike Green

You can connect a 50 Ohm speaker to a Stamp the same way you'd connect an 8 Ohm speaker to a Stamp. Both are not good matches. You'll get some output, but it'll be low volume. As Leon mentioned, you need an amplifier of some sort to get any reasonable volume, something as simple as a switching transistor like the 2N2222A or 2N3904 with a resistor in the base lead as shown in Nuts and Volts Column #6 substituting a speaker for a small motor. You may need a resistor in series with the speaker to limit the maximum current through the speaker. Something like 100 or 220 Ohms will do.