help signal conditionng

dr pepper said:

C3 is going to have a hard time too.

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dr pepper said:

Just what I was thinking.
C3 is going to have a hard time too.
Also looks like the feedback resistor is missing from the first op amp.

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rjenkinsgb said:

There is a component missing from that diagram, so it cannot work as shown.

It needs a additional resistor below R4 & the first opamp, connected between the negative input and the opamp output.

The left-hand opamp then forms a differential amplifier, giving an output proportional to the difference between the inputs at R1 & R2, as long as the inputs and output of the opamp stay within their working range for the supply voltage in use.
The actual input range is dependant on resistor values, opamp type and power supply voltages.

The second opamp and the components around that form a low-pass filter.
Again, the exact gain and frequency response are dependant on the component values.

More info on the "differential amplifier" configuration: http://en.wikiversity.org/wiki/Fund...Differential_amplifier_(difference_amplifier)

This is a low pass filter similar to your circuit:

Glossary of Electronic and Engineering Terms 'Op Amp Active Low Pass Filter'

LM 324 Low Pass Filter Circuit. Electrical Engineering Dictionary of Electronic Terms, LM324 Operational Amplifier Active Low Pass Filter schematic and operating description.

www.interfacebus.com

LTSpice is a suitable simulator, it is free and used by many people on this site:

http://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html

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