in a pulmonary diagnostic instrument that includes a breath transducer for use in conjunction with the instrumentation for detecting respiratory functioning of a patient or specimen , the transducer comprises a flow tube in which is suspended for lineal displacement a partial diaphragm generally constructed as a foraminous plate , and which during testing , the specimen &# 39 ; s breath flows therethrough to achieve some degree of displacement of said diaphragm . the diaphragm incorporates and operates in association with various ferrous rings for enhancing the transfer of magnetic lines of flux which are generated by a charged e - core for determining the extent of said lineal displacement which is representative of and can be interpreted to provide information pertaining to pulmonary functioning for diagnosis of the respiratory system of the specimen . in another embodiment charged capacitive plates replace the aforesaid ferrous rings and e - core , and through a developed capacitive imbalance caused by the breath induced diaphragm displacement providing information that may be interpretive of pulmonary functioning , or flow of air .