GB831715A - Improvements in athermapeutic apparatus - Google Patents

Abstract

831,715. Electrotherapeutic apparatus. DIAPULSE MANUFACTURING CORPORATION OF AMERICA. Aug. 22, 1958 [Oct. 4, 1957], No. 27047/58. Class 81 (2). Electrotherapeutic apparatus comprises an H.F. oscillation generator and amplifier, the output of which is controlled by a pulse generator and fed to a tuned output circuit. This results in high-frequency oscillations being administered to the patient in controllable, pulsed bursts whereby the total heating effect is kept within tolerable limits. A piezo-crystal 37, connected to a valve 38, feeds oscillations to a doubling circuit 46, 47, the output of which is passed to a further frequency-doubling stage 50, 65 coupled to a radio-frequency amplifier 8 comprising two tetrodes in push-pull. Control pulses are derived from a generator assembly 6 in which parallel-connected oscillator valves 27, 28 are supplied with high-voltage anode current received from a full-wave power pack 5, containing a tapped auto-transformer 15 and a step-up transformer 18. The pulse length is controlled by a switch 33, which varies the effective capacity of the grid-condenser assembly 32, while the pulse frequency is controlled by a switch 35, which determines the magnitude of the grid leak 34. The amplitude of the pulses is determined by the transformer tapping switch 16 and the pulsed output is connected through a step-up transformer 36, which is connected as the anode feed for the amplifier valves 55, 56. Consequently the H.F. output is dependent on the flow of anode current from transformer 36 and passes as a series of pulses of H.F. current through transformer 73 and coaxial cable 74 to a tuned circuit 13 in the applicator head. Specification 554,848 is referred to.