bipolar saturation
regions of operations are?
1. Active / linear 2. Saturation 3. Cut-off Defining this relationship with bipolar junction transistors?
Regions of operations for bipolar transistors have five different regions of operation, defined primarily by the bias of application: • Forward active (or simply active): The emitter-base junction is forward biased and the base-collector junction is reverse biased. Most bipolar transistors are designed to offer maximum common emitter current gain, βF, hereinafter, the active mode. If this is the case, the collector-emitter current is approximately proportional to the base current, but many times larger, the variations of the small base current. • Reverse-active (or inverse-active or inverted): By reversing the conditions bias towards the active region, a bipolar transistor reverses active mode. In this mode, the emitter and collector regions of the papers. Because most BJT is designed to maximize the current gain in forward active mode, the βF in reverse is a number (2-3 for ordinary germanium transistor) times smaller. This mode transistor is seldom used, is generally considered only for failsafe conditions and some types of bipolar logic. The reverse voltage break bias to the base may be an order of magnitude smaller in this region. • Saturation: With both junctions biased, a BJT is in saturation mode and facilitates driving high current from the sender to receiver. This mode corresponds to a logic "in" or a closed switch. • Limit: In the cut opposite polarization conditions of saturation (both junctions reverse biased) are present. Current flow there is very little, which corresponds to a logic of "off", or an open switch.
