Physiological applications and technical limitations of the RCA 5734 mechano‐electronic transducer tube are discussed. A variable protecting mount adapts this tube to full‐scale ranges of force from 5 g to 2.5 kg or more with a 5 volt swing on all ranges. Fundamental resonance frequency varies linearly with the range, from 40 to 300 cps. Amplitude distortion is small and restricted to small deflections. Frequency and phase distortion depend on the driving tissue but are small for myographic phenomena whose highest harmonic is generally around 15 cps. Adaptation of the 5734 tube to ballistocardiography (1&mgr; to 10&mgr; swing) is also shown.