I have question regarding using two different opamp circuits as one,

please have a look at the attachment,

I want this circuit to work as integrator as well as a differential amplifier using two switches,
one switch for integrator and the other for Differential,
when I press 'Integrator' switch, the capacitor C2 must be shorted and Resistor R4 must be opened so the circuit acts like Integrator , when i Press switch for Differential, C1 and R3 must be opened so the circuit become complete differential amplifier.....
i need some idea on how to open / short these components through a switch, is it possible using digital logics ?? ? Howw ?

please give me some idea.

Thank you

 

R4 is really redundant; you need 10k from the output to the inverting input in either case.

Have a look at the attached. I've removed R4, and used a CD4066 quad analog switch with a SPDT toggle switch and an NPN transistor as an inverter to control the analog switch inputs. The CD4066 adds some error to the circuit, as it has a nominal 150 Ohm resistance from input to output per channel when the "internal switch" is closed.

 

i am not very good in electronics :/ please provide some simple idea :S i have studied opamp , dld, basics of transistor so far so far

 

I'm sorry the last schematic was difficult to understand.

I changed it to just use a single DPDT (double-pole double-throw) switch instead.

The dashed line between S1a and S1b means that they both switch at the same time.