Method and apparatus for the production of the currents intended to be used enélectrothérapie

摘要

773,082. Electrotherapeutic apparatus. SOPROTEC SOC DE PROMOTION TECHNIQUE. Dec. 9, 1952 [Dec. 11, 1951], No. 31191/52. Class 81(2) In electrotherapeutic apparatus the conversion of the input durrent to a surging form is effected by oscillation generators either themselves supplied by the therapeutic, current or controlled by other means which is supplied by the therapeutic current. In the form shown a mains transformer T1 supplies two valves V1, V2, serving to rectify alternate half-waves. However, whereas the operating conditions of V1 are constant, the grid bias of V2 may be varied down to cut-off by the potential across R8 which is in the anode circuit of V4 and this is also cyclically biased to cut-off by a triode V3, which is made to oscillate by a phase changing network P connected to its grid. With this arrangement the half-waves passed by V2 are cyclically modulated in amplitude and their combination with the output of V1 provides a surging current of the desired form. The rate of surge may be changed by changing the period of oscillation of V3. Instead of valves it is also proposed to use contact rectifiers and also, where valves are used, the necessary oscillation may be maintained by a relay of which the winding is connected in the anode circuit and the break contact is connected in the filament circuit.