) is a parameter defining the differential DC voltage required between the inputs of an amplifier, especially an operational amplifier (op-amp), to make the output zero (for voltage amplifiers, 0 volts with respect to ground or between differential outputs, depending on the output type).
However, due to manufacturing process, the differential input transistors of real op-amps may not be exactly matched.
are around 1 to 10 mV for cheap commercial-grade op-amp integrated circuits (IC).
However, the input offset voltage value may drift with temperature or age.
The voltage offset due to these currents is separate from the input offset voltage parameter and is related to the impedance of the signal source and of the feedback and input impedance networks, such as the two resistors used in the basic inverting and non-inverting amplifier configurations.