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Basic Principles of Electricity

Basic Principles of Electricity. Electromagnetic Spectrum. Electrical Stimulating Currents. Longest Wavelength. Lowest Frequency. Commercial Radio and Television. Shortwave Diathermy. Microwave Diathermy. Infrared. {. LASER. Visible Light. Ultraviolet. Ionizing Radiation. Highest

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Basic Principles of Electricity

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  1. Basic Principles of Electricity

  2. ElectromagneticSpectrum Electrical Stimulating Currents Longest Wavelength Lowest Frequency Commercial Radio and Television Shortwave Diathermy Microwave Diathermy Infrared { LASER Visible Light Ultraviolet Ionizing Radiation Highest Frequency Shortest Wavelength

  3. Electrons • Particles Of Matter Possessing A Negative Charge And A Small Mass • Net Movement Of Electrons Is An Electrical Current • Movement Of Electrons Is Like A Domino Reaction • Electrons Will Move From Higher To Lower Potential

  4. Ampere • Unit Of Measure Which Indicates Rate At Which Electrons Flow • 1 amp = movement of 1 coulomb or 6.25x1018 electrons /sec • Current Flow Is In Milliamps (1/1000) Or Microamps (1/1,000,000)

  5. Electrical Potential Difference • Difference In Concentration of Electrons Between Two Points • Electrons Will Not Move Unless A Potential Difference Exists

  6. Volt • Creates The Potential Difference • The Electromotive Force Which Must Be Applied To Create Flow Of Electrons • Commercial Current Is 120 V or 220 V

  7. Conductors • Materials That Permit Free Movement of Electrons • Composed Of Large Numbers of Free Electrons • Offer Little Resistance To Current Flow • Good Conductors • Metals (copper, gold, silver, aluminum) • Electrolyte Solutions

  8. Insulators • Materials That Resist The Flow Of Electrons • Contain Few Free Electrons • Insulator Materials • Air, Wood, Glass

  9. Resistance = Electrical Impedance • Opposition To Flow Of Electrical Current • Measured In Ohms • Ohm’s Law Current Flow= Voltage Resistance

  10. Watt • Measure of Electrical Power • Watts = Volts X Amps • Modalities Use Milliamps or Microamps

  11. Electrotherapeutic Currents • Direct (DC) or Monophasic • Flow of Electrons Always In Same Direction • Sometimes Called Galvanic

  12. Electrotherapeutic Current • Alternating (AC) or Biphasic • Flow of Electrons Changes Direction • Always Flows From Negative to Positive Pole Until Polarity Is Reversed

  13. Electrotherapeutic Currents • Pulsed or Polyphasic • Pulses Grouped Together and Interrupted • Russian and Interferential Currents

  14. Electrical Generators • All Are Transcutaneous Electrical Stimulators • Transcutaneous Electrical Nerve Stimulators (TENS) • Neuromuscular Electrical Stimulator (NMES) = Electrical Muscle Stimulator (EMS) • Microcurrent Electrical Nerve Stimulators (MENS) = Low Intensity Stimulators (LIS)

  15. Electrotherapeutic Currents • No Relationship Between Type Of Current Used To Power Generator and Type Of Current Output To Patient • Generators May Be Powered By AC or DC • Batteries = DC between 1.5 and 9 V • Wall Outlet = AC at 120 or 220V at 60 Hz

  16. Waveform or Pulse • Pulse= Individual Waveform • Phases (Duration) • Interpulse Interval • Direction (Polarity) • Amplitude • Rate Of Rise • Rate of Decay • Accommodation

  17. Symmetrical Waveforms • Sine • Square • Triangular

  18. Symmetrical Waveforms • Twin Peaked Triangular Waveform • Found on Most High Volt Generators

  19. Asymmetric Waveforms • Faradic • Exponential • Sawtooth

  20. Current Modulation • Continuous • Interrupted • Burst • Packets • Pulse Trains • Beats • Ramped (Surge)

  21. Pulse Amplitude • Same As Intensity or Voltage • Measured In Milliamps or Microvolts • Average Current Determined By Interpulse Interval Or Current Duration

  22. Pulse Duration • Length Of Time Current Is Flowing • With Monophasic Current Phase Duration Is the Same As Pulse Duration • With Biphasic Current Pulse Duration Is Determined By The Combined Phase Durations • With Polyphasic Current The Combined Pulse Duration And Interpulse Interval Is The Pulse Period

  23. Pulse Frequency (CPS, PPS, Hz) • Effects The Type Of Muscle Contraction • Effects The Mechanism of Pain Modulation

  24. Electrical Circuits • Path of Current From Power Source Through Various Components Back To Generator • Power Source-Conducting Medium - Component Resistors • Series Circuit • Parallel Circuit

  25. Series Circuit • One Path For Current To Take • Component Resistors Placed End To End • Total Resistance = Sum of Resistances • Total Voltage = Sum of Voltage Decreases

  26. Parallel Circuit • Component Resistors Placed Side to Side With Ends Connected • Current Chooses Path With Least Resistance • Resistors Have Lower Resistance But Higher Current Flow Than A Series Circuit

  27. Current Flow Through Biologic Tissues • Combination Of Both Series And Parallel Circuits • Tissue Highest In Water And Ion Content Best Conductors - Blood, Nerve, Muscle, Tendon, Skin, Fat, Bone

  28. Safety In Using Electrical Equipment

  29. Ground Fault Interruptors • Constantly compare amount of electricity flowing from wall outlet to whirlpool turbine with the amount returning • GFI will interrupt current flow in as little as 1/40 of a second

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