Short Wave Diathermy (SWD) Frequency (ƒ) 10 7 – 10 8 Hz Radio wavelength (λ) 3 -30 m Commonly used frequency (ƒ) is 27.12 MHz and wavelength 11 m. It this current two circuits are used. Machine circuit is coupled with the patient circuit leading to resonance phenomenon, in this way patient is treated. A. Machine circuit: The basic oscillator circuit consists of condenser, inductance, and the currents of different frequencies are obtained by selecting suitable condenser and inductance. It a current of very high frequency is required, the condenser and inductance are very small. While to produce a current of lower frequency a larger condenser and inductance is used. B. Patient circuit: When SWD is applied by the condenser field method, the electrodes in the patient tissues form a capacitor, the capacitance of which depends upon the size electrodes and distance material between them. When the oscillator and resonator circuits are in t
Phyaction 787 Multistimulator Interface and electrodes 1-Faradic Current 2-Transcutaneous Electrical Nerve Stimulation (TENS) 3-Interrupted Direct Current 3-Interfrential Current 3-Didynamic Current
Therapeutic Ultrasound Sound is the mechanical disturbance of an elastic medium such as air. Vibrations which travel through the air or another medium are called as sound. The frequency of hearing sound is 20Hz – 20,000Hz. Ultrasound means the above the frequency of sound or the sound waves which are produced above the 20,000 Hz. Production of Ultrasound: For a one mega Hz frequency machine vibrating source with a frequency of one million pulses/s (million cycles/s) is needed. This is achieved by using either quartz crystal or barium crystal. These crystals deformed when subjected to various potential differences (Piezoelectric effect). The basic components of Ultrasound apparatus are the following. o Source if high frequency current o Cable o Link electrodes o Barium or Quartz crystal o Metal plate Working: Source of high frequency current which is conveyed via co – axial cable to a transducer circuit or ultrasound head. Inside th
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