Regarding "straining the op amp" in the non-inverting mode, I believe the writer was refering to the fact that in non-inverting mode, there is a large common mode voltage on the input in non-inverting mode, while the common mode voltage in inverting mode is zero. For some notes on using what I call "the theory of the happy op amp" (differential input voltage ideally zero), see http://kauko.hallikainen.org/cuesta/et113/InstrumentationAmpAnalysis.pdf . This is an analysis of an instrumentation amplifier using this approach. Harold > The input impedance of a non-inverting configuration is significantly > higher. That is an important consideration when the signal to be > amplified > or buffered is relatively small. The trade-off, however, is that the > non-inverting configuration tends to be less stable around zero than the > inverting configuration. If you are working with AC signals it may not > add significantly to your error budget but if you are designing DC control > then you may want to account for this, depending on your budget and > application. The inverting configuration is usually more desireable in > precision applications. Non-inverting is good for things like video > applications, etc. Non-inverting buffers, such as the old LM310, for > example, have a very high open loop gain to help stabalize the near-zero > operation. The open loop gain is much higher than for a typical op-amp. > If > you are going to work with DC near zero, you may want high open loop gain > devices when designing a non-inverting circuit. > > > ----- Original Message ----- > From: "Luis Moreira" > To: > Sent: Friday, June 11, 2004 6:07 AM > Subject: [EE] OPAMP use > > >> Hi Guys >> For years I been using the inverting OPAMP circuit when amplifying a > signal, >> by using two stages to get the signal in the right phase. But Now >> someone >> that works with me just designed a circuit with a non inverting OPAMP >> configuration, and apart form the fact the gain can not be lower than 2 >> I >> can not see any problems with using this configuration. in top of it all >> I >> only need one OPAMP not two. >> I read a few things about it and it seems that the non inverting >> configuration puts more strain on the OPAMP... >> Do any of you have any info on this and any other problems that could > arise >> by using this configuration over the inverting one. >> best regards >> Luis >> >> -- >> http://www.piclist.com hint: The list server can filter out subtopics >> (like ads or off topics) for you. See http://www.piclist.com/#topics >> > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > -- FCC Rules Online at http://www.hallikainen.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics