 The value of this gain for DC signals is referred to as formula_4, and the value of this gain for small signals is referred to as formula_5.That is, when a small change in the currents occurs, and sufficient time has passed for the new condition to reach a steady state formula_5 is the ratio of the change in collector current to the change in base current.The symbol formula_7 is used for both formula_4 and formula_5.