GB460745A - Apparatus for diathermic treatment - Google Patents

Abstract

460,745. Valve generating circuits. STANDARD TELEPHONES & CABLES, Ltd. (Federal Telegraph Co.) March 27, 1936, No. 9178. [Class 40 (v)] [Also in Group VI] In a diathermy apparatus comprising a high-frequency oscillator and an output circuit coupled thereto, the output circuit comprises an inductance 34 and a variable condenser 36, the mid points of both of which are earthed through a high-frequency choke 35 and directly respectively. As shown, the circuit includes coils 32, 33 constituting the coupling to the oscillator, and the condenser 36 comprises two equal series condensers the inner plates of which are movable as a unit. A measuring circuit across coil 34 includes a thermocouple 37 connected through highfrequency chokes 38 to a direct-current meter 40 shunted by a condenser 41 to byepass highfrequency current : 42, 43 are the patient terminals. The oscillator comprises inductances 31, 29, connected respectively to the anodes 19, 20 and the grids 21, 22 of a pair of valves 17, 18. The mid points of coil 31, 29, are connected through high-frequency chokes 30, 28 to the opposite ends of the secondary of a mains transformer 23. an intermediate point 26 of which is earthed. A condenser 27 absorbs mains-frequency currents. The valve filaments are supplied from the secondary of a mains transformer 5 through terminals on a terminal strip 2, one of which is earthed, and chokes 10, 11. A voltmeter 14 having a high-frequency byepass condenser 15 is connected across the filaments through high-frequency chokes 12, 13. The primaries of transformers 5, 23 are provided with tappings for various voltages and are connected to a mains plug 1 through the terminal strip 2 and a mains switch 3, a rheostat 4 being provided for transformer 5. The point 26 in transformer 23 may be connected directly to the filament circuit instead of being earthed. A blower 16 energized from the mains is employed to cool the apparatus within its enclosing cabinet.