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Cutting and coagulation of skin.

The iSurg(MC6B) is an isolated output monopolar electrosurgical generator configured as a table top standalone device, Height 3.5in (89mm), Width 10.5in (267mm), Depth 6.5in (165mm), Weight 6lb (2,73kg) It produces 50 watts into 500 ohms at 3.0 MHz. The iSurg(MC6B) generates RF current via an AM modulated power oscillator comprised of a class C beam power vacuum tube Hartley oscillator. The power oscillator runs at full power when actuated. Power control is by means of an attenuator in the form of variable air capacitor. MOPP (Means of Patient Protection) is in the form of magnetic coupling to an isolated winding on a separate core in the RF coil providing type BF floating patient applied parts in accordance with IEC 60601-2-2. The RF coil primary serves as an intermediate stage with PE connection. MOOP is provided by the low voltage control board (61.010) which galvanically isolates the foot pedal from mains and earth and couples to the oscillator through opto-coupler and relay. SELV common on this board floats. The 81.001A Switch Board uses high isolation relays powered by the low voltage board to isolate the relay coils from the oscillator board. Oscillator actuation is by means of earthing the cathode of the beam power tube via a relay; oscillator OFF state is when the cathode of the beam power tube floats. Tube bias is by means of grid leak via the 10K grid load. The 10K grid load resistor is wire wound type with significant inductance: the current to ground through it is close to DC accordingly. It is current through this resistor that is sensed for the RF ON indicator and active tone (a function of the low voltage control board). The low voltage board also includes a warm up delay to prevent cathode stripping of the vacuum tube.