The RSP100C is designed for direct physical measurement of respiratory effort. The RSP100C works with the TSD201 transducer to measure abdominal or thoracic expansion and contraction while breathing. The RSP100C permits DC coupling to the TSD201 for the recording of respiratory effort signals of arbitrarily low frequency. Front panel controls allow selection of absolute or relative expansion/contraction measurements. Each RSP100C amplifier requires one TSD201 respiration transducer, shown in the transducer section.