differential op amp design?

Question

can somebody help me design a differential op amp given:

V0 = -0.002dx/dt

where x = 2sinwt and f = 100Hz.
Please show computation. Thanks

Answer 1

I answered your integrator question and this circuit, a differentiator, is the inverse of the integrator. Similar to the integrator, you use an op amp with the differentiation function supplied by negative feedback. Since you require a negative gain times the derivative, you apply the signal to the inverting input. The signal enters via a series capacitor Ci and the feedback loop consists of a resistor Rf connected from output to inverting input. The time constant Rf*Ci should be 0.002 sec. Reasonable values would be Rf=100 Kohm, Cf=0.02 uF, but there is considerable flexibility to accommodate goals of, e.g., low input signal loading, low susceptibility to cross-coupling, etc. Ref. 1 explains the theory.
The output will be the derivative of 2 * sin(w*t) = 2 * cos(w*t) * w, times -0.002, or about -2.51*cos(w*t).
Differentiators can sometimes be troublesome because of their high-frequency gain, which increases without theoretical limit as frequency increases, and may cause instability or overload problems when signals with high harmonic content such as square waves are input. Sometimes an additional, small capacitance Cf is placed in parallel with Rf to limit high-frequency gain. As with the integrator, such corrections can change the gain at the desired frequency, but adjustment to the input capacitor can be made to compensate if necessary. See ref. 2, section 5.

Answer 2

An op-amp (operational amplifier) is an instant coupled amplifier with 2 inputs; an inverting enter and a non-inverting enter. The output of the amplifier (v_out) is the amplification cost (A) bigger via the version between the non-inverting (v+) and inverting (v-) voltages. v_out = A*(v+ - v-) The amplification cost is extremely intense, so op-amps are often used with comments to decrease their amplification in return for precision. there are a number of books written approximately op-amps. There are 2 common closed-loop (i.e. that have comments components linked from the enter(s) to the output) configurations: inverting and non-inverting.