The M100 series of frequency transducers are designed to measure frequency in single and 3 phase systems. The A. C. Input is converted to a D.C. Output, that is directly proportional to the change in input frequency within a specified span. The M100-FA1 is self powered. (No auxiliary required). The working voltage range is 75-125% of the nominal voltage. The M100-FL1 is auxiliary powered. The outputs are live zero either 4mA or 1 volt. The auxiliary enables the working voltage range to be 15-125%. The M100-FX is essentially the same as the FA1 but an auxiliary is provided to enable the unit to have a working voltage range of 15-125%. All types of the above frequency transducers are typically used to monitor and control frequency in such applications as 3 phase mains supplies, A. C. Generating sets and process control, etc.