Inngangsoffsetstrømmen

Inngangsoffsetstrømmen, often referred to as input offset current, is a parameter associated with operational amplifiers (op-amps) and other electronic components that have differential inputs. It quantifies the small difference in input currents that is required to bias the op-amp into its linear operating region. Ideally, the input bias currents at both input terminals of an op-amp should be equal. However, due to manufacturing imperfections and variations in the internal circuitry, a small difference in these currents typically exists.

This difference is defined as the input offset current. It is usually a very small value, measured in nanoamperes (nA) or picoamperes (pA). The input offset current is a significant factor when dealing with high-impedance circuits or applications requiring precise DC voltage levels. If not accounted for, it can lead to an output voltage error. This error is directly proportional to the input offset current and the resistance of the feedback network.

Minimizing the impact of input offset current can be achieved through various techniques. One common method is to select op-amps with very low input offset current specifications. Another approach involves using a "compensation resistor" in series with one of the input terminals. This resistor is chosen to match the equivalent resistance seen by the other input, thereby balancing the voltage drops caused by the bias currents and reducing the output error. Understanding and managing input offset current is crucial for achieving accurate and stable performance in analog circuit designs.