BIPOLAR LOGIC CIRCUIT

PURPOSE:To extract the charge of the base independently of an output load capacity by conducting a 4th transistor(TR) with respect to the conduction of a 1st TR and discharging the base charge of a 2nd TR. CONSTITUTION:A current is supplied to an output terminal 3 from a high potential power connection terminal 1 via a resistor 25 and a potential at the output terminal 3 goes to a high level. On the other hand, when a high level signal is inputted to a base of an npn TR 11 with SBD, which is conductive resulting that npn TRs 14, 16 with SBD are conductive, the potential at the output terminal 3 goes to a low level, and the level at the output terminal 3 changes from a high to a low level. By such an operation, an emitter current of the npn TR 11 with SBD makes the npn TR16 with SBD conductive at first. Thus, the charge stored on the base of an npn TR 13 is discharged in response to the current amplification factor of the npn TR 16 with SBD.