DC offset

DC offset is a characteristic value of operational amplifiers caused by circuit tolerances. It is the differential input voltage that can be measured when the output voltage is zerovolts.

Although the output voltage is zero volts, a small DC voltage may be present at the inputs. Such voltages can already occur due to differential input currents, which are due to the tolerances of the input resistors or the base currents of the input circuit. Since the DC offset is disturbingly noticeable, it must be compensated by appropriate circuitry.