How to connect a 8-Ohm speaker to the BS-2?
I have to connect a 8-Ohm Speaker to my BS-2. How?
Can I connect it directly or via a transistor?
Thanks.
Nicolas
Can I connect it directly or via a transistor?
Thanks.
Nicolas
Comments
·· There is an example schematic for this right in the Editor Help File under the FREQOUT command.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Or follow Chris' advice since it will likely be a simpler circuit to construct.
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1+1=10
In this schematic It dose not put a # to this chip
Can any one tell me what chip was used in this link below
http://www.parallax.com/dl/docs/prod/boards/PDBSchem.pdf#page=3.
This is the schematic It dose not put a chip #
I want to built this circuit
Thanks to any one that can help with this
Sam
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1+1=10
Post Edited (PJ Allen) : 4/29/2006 3:18:46 PM GMT
Consider Ohms law ([noparse][[/noparse]E=IxR] 5volts / .025 amps = 200 ohms) and you will see why people are suggesting 220ohm resistors as protection for the Stamp.
Anything much lower will burn out the I/O pins.
Thus, the handy LM386 is recommended. Is that the handy little 5 watt audio amp chip?
If you just want to get sound, a transistor or a darlington might do the trick too.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
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1+1=10
· It's a 1kohm:8ohm audio transformer.· The only other components needed are a 10uF cap and a 330ohm resistor.· I'm using a HomeWork Board, which has the built-in 220ohm resistors on the I/O.· If that's not your situation, use a 470ohm instead of the 330ohm.
· Drawing/schematic attached.
**** Post Edit ****
· My nearest Radio Shack still stocks·the "miniature audio output transformer", #276-1380 273-1380.· [noparse][[/noparse]N.B. -- Don't buy the other one, the 1:1,·it's for something else.]
· Also, they've had outstanding pricing (I think) on 'AA' & 'AAA' batteries·selling·40-packs for $19.99 [noparse][[/noparse]that's 50c each].· Well, they've made it even better, those same 40-packs are now $16.99 [noparse][[/noparse]that's 43c each]!!!· The packs I bought are dated for 2010 (so it's·not like a sale on lunch-meat.)·
· Zip-Zaps are Clearance Priced, too -- $12.47.
Post Edited (PJ Allen) : 4/30/2006 4:08:54 PM GMT
Thanks for your reply
Sam
·
Thanks for posting this
Pity that we've forgotten, or relegated to obscurity, our old friend -- the audio output transformer (still available at Radio Shack.)· audio_xfmr.jpg · 44KB (image/pjpeg)
That just what i was looking for
Sam
Post Edited (sam_sam_sam) : 4/30/2006 12:57:02 AM GMT
Thanks for pointing that out. As a newcomer to the hardware side of things it's good to hear about other ways to do things. Especially when they are cheap enough to experiment with just for the fun of it.
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OS-X: because making Unix user-friendly was easier than debugging Windows
Just to re-emphasize the problem. Don't EVER put the 8 ohm side of the transformer to the BasicStamp. That 220 ohm resistor may be there to save you on the Homework board, but not in all situations.
Everything under 200 ohms should be questioned.
Everything over 25ma should be questioned.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Kramer -- You're right, nobody·better put an 8ohm speaker directly to the output ("double-plus un-good" ).
· The PBASIC Help shows one way to use a speaker.· They use a 47ohm resistor in series with an 8ohm speaker.· I can tell you that using the transformer,·however imperfect,·results a lot more volume at the speaker, because it doesn't·have nearly·all the output across the non-transducing resistor (as in the PBASIC resistor-speaker configuration.)
· nboucquey wanted to know of some way to do this.· I assumed it was for tones, alarms, beeping purposes (and for such I reckon this is a winner.)
I suppose that can squeeze about as much volume as possilble out of a BasicStamp without an amplifier.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan