Hello Roland and PIC.ers, Take a look at the Analog Devices AD7730 or AD7715, these seem to fit your bill well. .. They can act as complete diff. amp (IA), PGA, exciter, ADC, digital filter etc., etc., all rolled into one. The great attraction is the possibility of high-res strain-gauge measurement without having to dig the signal out of the noise afterwards. Altogether PIC-friendly too. .. These are not very cheap, Analog Data Products in Midrand, tel (011) 805 6507, offer them for ~R84 (7730) and ~R53 (7715). That's still good news. The bad news is that they never have stock...... .. Best regards, John >Date: Tue, 9 Jun 1998 12:07:23 GMT+2 >From: Roland Andrag >Subject: Amplification vs. high res A/D >Hello all... >This is sort of off topic, but not really, so I didn't include the >OT... Here goes: >I'd like to get the feeling of the group regarding the input of a >small analogue signal (say 0-100 mV). The choice lies between using a >differential amp to get 0-5 V and using an 8 bit (possibly internal) >A/D to get it into the PIC, or to simply use a 12-bit A/D without >amplification... >For the direct use of a higher res A/D my next question would be >whether A/D converters are available that accept differential inputs >(from a Wheatstone bridge sort of arrangement).. Battery powered, >single supply (0-5 V)... .. email from John Sanderson at JS Controls, PO Box 1887, Boksburg 1460, Rep. South Africa Manufacturer & purveyor of laboratory force testing apparatus and related products and services. Tel/fax: Johannesburg 893 4154 Cellphone 082 453 4815