Binary input, BCD counter - uses four flip=flops for each decade whose main bistable elements are two transistors with base resistors

摘要

The counter comprises four flip-flops for each decade enabling each decade to be represented by a four bit binary code. An AND gate detects a count of 10 on any decade and immediately resets these four flip-flops to zero and initiates a count of 1 in the next decade. Each flip-flop comprises two transistors with bare resistors connected to the collector of the other transistor.