An AC Frequency Transducer is a device that measures the frequency of an AC signal (in Hertz, Hz) and converts it into a proportional output signal, typically 0–10V DC or 4–20mA, which can be used by PLCs, controllers, or monitoring systems. In simple terms, it takes the frequency of an AC supply (like 50 Hz) and converts it into a standard analog signal for easy processing and control.