A frequency counter is an electronic device used to measure the frequency of an input signal. It counts the number of cycles of a waveform that occur in a specific time period, providing a precise measurement of frequency in hertz (Hz). Frequency counters are commonly used in various fields, including telecommunications, electronics, and audio engineering. These devices can handle a wide range of frequencies, from very low to very high, depending on their design. Some frequency counters also offer additional features, such as the ability to measure period, time interval, and pulse width, making them versatile tools for engineers and technicians working with signals and waveforms.