Page 1122 - Basic Electrical Engineering

Thus, the output voltage, V is the difference of the two input voltages and
0
is multiplied by a factor R /R .
2
1
Now we will consider the use of an op-amp as a differentiator and as an

integrator.

17.6.3 Op-amp As a Derivative Amplifier

In a differentiator, the output voltage is proportioned to the derivative of the
input voltage with respect to time. As in previous cases, the point Q is

assumed to be at zero potential. Virtually no current flows through the
amplifier as it has infinite input impedance and infinite gain. The charge on

the capacitor, q is equal to

q = CV 1

∫ idt = CV 1

or,

Again

Assuming v = 0,

using equations (vi) and (vii),

or,