


Operational Amplifiers (Opamps) 


The introduction of the μA741 operational amplifier (opamp, opamp, op amp) integrated circuit in 1968
significantly changed the analog design philosophy from on where every amplifier circuit was designed with
individual transistor amplifiers, to a more "packaged" approach. Due to the opamp's unique characteristics (see
below), it became possible to apply simple formulas to standard configurations for creating many circuits. There
are many "cookbooks" available that contain hundreds of configurations covering everything from simple amplifiers
to complex filters, differentiators, integrators, multibreakpoint frequency responses, even logarithmic
amplifiers.
Standard nodal analysis can be used to perform opamp circuit analysis, including the
properties of superposition. Here are a few of most often found opamp configurations that are found either by
themselves, or as part of more complex circuits.
Ideal opamps assume the following properties:
*
Infinite open loop gain * Zero output impedance * Infinite input impedance * Infinite bandwidth
NonInverting

Inverting


Differentiating
At any single frequency the gain is:

Integrating
At any single frequency the gain is:

Differential




