Get National Semiconductor's application note AN-74 from:

http://www.national.com/apnotes/ap_notes_all.html

Figure 30 shows a circuit that looks like what you want.



At 11:02 AM 1/9/98 +0500, you wrote:
>Hi to all.
>
>I need one linear amplifier and three comparators in my PIC project. I
>intend to use a quad comparator LM339. Can I use a spare comparator of this
>chip as a  linear amplifier? The magnitude of the amplifier must be about
>100, frequency range 100-5000Hz.
>
>
---------------------------------------------------------------------------
Lynn Richardson - Design Eng.|WA0ZNL            |Progress Instruments, Inc.
DC - 1GHz, RX, TX 100W, PLL  |WA0ZNL.AMPR.ORG   |807 NW Commerce Drive
ASM 6805, 8051, Z8, PIC      |44.46.176.3       |Lee's Summit, MO 64086
C                            |lrich@proginst.com|P(816)524-4442 F 246-4556