Base coupled logic circuit with differential amplifier - has two transistor base terminals commoned and coupled to earth across resistor

摘要

The base coupled logic circuit is intended for negligible switching delay and power losses and has two amplifier stages each with a npn transistor differential amplifier. The base terminals of both transistors (T1, T2) are commoned and coupled to earth (UBO) across a resistor (RO). The emitter terminal of the first amplifier stage transistor is connected directly to the signal input (E) and to the operating voltage (UB1) across a resistor (R3). The emitter terminal of the second amplifier stage transistor is connected directly to a second operating voltage (UB2) so chosen that the second transistor is blocked if the input signal is missing. The signal output is connected to the collector terminal (A, A) of one transistor.