Operational amplifier basic circuits

There are some standard op-amp circuit that are often used. Because of it’s high gain, the calculations becomes easy. Mostly, the op-amp is used in a negative feed-back configuration, feeding the output back to the negative input. This will limit its gain, making useful applications of the op-amp.

Voltage Follower

Voutput = Vinput

Inverting Amplifier

Voutput = -R2/R1*Vinput

Non-Inverting Amplifier

Voutput = (1+R2/R1)*Vinput

Difference Amplifier

If R1=R3 and R2=R4 then
Voutput = R2/R1*(Vinput2 – Vimput1)

Inverting Summing Amplifier

Voutput = -R4(Vinput1/R1 + Vinput2/R2 + Vinput3/R3 + … )

Non-Inverting Summing Amplifier

Voutput = (Vinput1 + Vinput2 + Vinput3 + …)*(1+(R5/R4))/NumberOfInputs

Integrator

Differentiator

If R1 << R2 then

Files:
http://www.lamja.com/blogfiles/VoltageFollower.asc
http://www.lamja.com/blogfiles/InvertingAmplifier.asc
http://www.lamja.com/blogfiles/NonInvertingAmplifier.asc
http://www.lamja.com/blogfiles/DifferenceAmplifier.asc
http://www.lamja.com/blogfiles/InvertingSummingAmplifier.asc
http://www.lamja.com/blogfiles/NonInvertingSummingAmplifier.asc
http://www.lamja.com/blogfiles/Integrator.asc
http://www.lamja.com/blogfiles/Differentiator.asc