A decade counter is an electronic device that counts from 0 to 9 and then resets to 0, effectively counting in decades. It is commonly used in digital circuits to keep track of time or events, often found in applications like clocks and timers. The counter operates using flip-flops, which are basic building blocks in digital electronics. These counters can be implemented using various technologies, including integrated circuits and microcontrollers. They are essential in digital systems for counting purposes, providing a simple way to manage sequences and events in a controlled manner.