Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!ncr-sd!ncrlnk!ncrwic!encad!entec!kthompso
From: kthompso@entec.Wichita.NCR.COM (Ken Thompson)
Newsgroups: sci.electronics
Subject: Re: Attaching a PC speaker to an amplifier
Message-ID: <545@entec.Wichita.NCR.COM>
Date: 5 Apr 90 14:18:54 GMT
References: <1733@sparko.gwu.edu>
Reply-To: kthompso@entec.Wichita.NCR.COM (Ken Thompson)
Organization: NCR Corporation, Wichita, KS
Lines: 31
Keywords:

If you REALLY think you need to amplify it...

Yes you will need caps. to isolate the DC voltages of the PC from the amp.

The speaker circuits I have seen in PC's have one side of the speaker
tied to +5V and the other to and emiter follower PNP transistor.
Neither speaker termainal is at ground.  Use two caps:



|\   
| \
|  |
|  |----------------||------------> to amp
|  |        |
|  |---+------------||------------>   
|  |   |    | 
| /    |    |
|/     |    |

spkr    feed      isolation
         to          caps
        spkr



-- 
Ken Thompson     N0ITL  
NCR Corp.  3718 N. Rock Road            
Wichita,Ks. 67226  (316)636-8783       
Ken.Thompson@wichita.ncr.com