A decade counter is a type of digital counter circuit that counts in decimal (base-10) increments. It is designed to count from 0 to 9 and then reset back to 0, hence the name "decade" counter. Each output of the counter represents a single digit in the decimal counting sequence.
There are different types of decade counters, such as asynchronous (ripple) counters and synchronous counters. The most common type is the synchronous decade counter, which is synchronized to a clock signal, ensuring accurate and synchronized counting.
The maximum count of a decade counter depends on the number of output stages it has. A typical decade counter consists of four flip-flops (also known as stages), which can represent a binary count from 0000 to 1001 in binary notation, which is 0 to 9 in decimal notation. After reaching the count of 9 (1001 in binary), it resets to 0 (0000) and starts counting again.
In this configuration, the decade counter can count from 0 to 9, providing a total of 10 different counting states. The count range can be extended by cascading multiple decade counters together, where the output of one counter feeds as the clock input of the next counter. By doing this, you can create a counter with more stages to count to higher values. For example, two cascaded decade counters can count from 0 to 99, three cascaded counters from 0 to 999, and so on, with each additional counter expanding the count range tenfold.