Metningsområdet

Metningsområdet, often translated as saturation region or saturation zone, refers to a condition in a semiconductor device, most commonly a bipolar junction transistor (BJT) or a field-effect transistor (FET), where the device is operating at its maximum current capacity for a given set of input conditions. In BJTs, this occurs when the base current is sufficiently large to drive the collector current to its theoretical maximum, which is primarily limited by the external circuit and the device's physical properties rather than the base current. In this state, further increases in base current do not result in significant increases in collector current.

For FETs, the saturation region is characterized by the drain current being largely independent of the drain-source voltage and primarily controlled by the gate-source voltage. This occurs when the channel between the drain and source is "pinched off" near the drain end due to a sufficiently high gate-source voltage. In both transistor types, operating in the saturation region typically implies the device is acting as a current source or is in a state of full conduction, meaning it's allowing as much current as it can. This region is distinct from the active region, where the transistor acts as an amplifier, and the cutoff region, where the transistor is essentially switched off. Understanding the metningsområdet is crucial for designing circuits that utilize transistors as switches or as stable current sources.