## 计数器

### 原理
  * [[https://www.electronicshub.org/introduction-to-counters/|计数器介绍]]
  * [[https://www.electronicshub.org/synchronous-counter/|同步计数器]]
  * [[https://www.electronicshub.org/asynchronous-counter/|异步计数器]]
  * [[https://www.electronicshub.org/decade-counterbcd-counter/|外部链接]]
  * [[https://www.electronicshub.org/ring-counters-johnson-ring-counter/|环形计数器和扭环形计数器]]
  * [[https://www.electronicshub.org/ic-4017-decade-counter/|外部链接]]

### 案例
  * [[ring_counter|环形计数器]]
  * [[johnson_ring_counter|扭环形计数器]]
  * [[freq_div|分频器]]
  * [[second_watch_counter|秒表计数器]]