Binary-coded-decimal counter - has string of flip=flops each comprising two cross-coupled transistors and connected via coupling transistors

摘要

The counter, for an 8421 code, consists of a string of flip-flops each coupled to its neighbour via a transistor. The transistors are controlled by the count outputs of the flip-flops or from the reset outputs of the flip-flops as required. Each flip-flop consists of two cross-coupled transistors each connected via a diode and capacitor to one main electrode of that flip-flop's associated coupling transistor. The output of one flip-flop transistor is connected to the base of its associated coupling transistor.