Dc Current Gain Common Base — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
DC Current Gain (Common Base) Applies to Bipolar Junction Transistors (BJT) operating in the Active Region, specifically for DC analysis in Common Base configuration. In Common Base configuration, the input current is the Emitter current ( I E ) and output current is the Collector current ( I C ). The current gain is defined as the ratio of output current to input current. Therefore, DC Current Gain dc = I C I E . I E > 0 I C < I E Active Region operation implies base-emitter junction is forward biased and collector-base junction is reverse biased. Confusing alpha (Common Base gain) with beta (Common Emitter gain). Assuming alpha can be greater than 1 (it is always slightly less than 1). Ignoring leakage current (ICBO) in very precise calculations, though negligible in basic problems.