Basic Principles of Basic Principles of ElectricityElectricity

ElectromagneticElectromagneticSpectrumSpectrum

Electrical Stimulating CurrentsElectrical Stimulating CurrentsCommercial Radio and TelevisionCommercial Radio and Television

Shortwave DiathermyShortwave DiathermyMicrowave DiathermyMicrowave Diathermy

InfrareInfrareddLASERLASER

Visible LightVisible Light

UltravioletUltraviolet

Ionizing RadiationIonizing Radiation

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LongestLongestWavelengthWavelength

ShortestShortestWavelengthWavelength

LowestLowestFrequencyFrequency

HighestHighestFrequencyFrequency

ElectronsElectrons

Particles Of Matter Possessing A Particles Of Matter Possessing A Negative Charge And A Small MassNegative Charge And A Small Mass

Net Movement Of Electrons Is An Net Movement Of Electrons Is An Electrical CurrentElectrical Current

Movement Of Electrons Is Like A Movement Of Electrons Is Like A Domino ReactionDomino Reaction

Electrons Will Move From Higher To Electrons Will Move From Higher To Lower PotentialLower Potential

AmpereAmpere

Unit Of Measure Which Indicates Unit Of Measure Which Indicates Rate At Which Electrons FlowRate At Which Electrons Flow• 1 amp = movement of 1 coulomb or 1 amp = movement of 1 coulomb or

6.25x106.25x101818 electrons /sec electrons /sec Current Flow Is In Milliamps Current Flow Is In Milliamps

(1/1000) Or Microamps (1/1000) Or Microamps (1/1,000,000)(1/1,000,000)

Electrical Potential Electrical Potential DifferenceDifference

Difference In Concentration of Difference In Concentration of Electrons Between Two PointsElectrons Between Two Points

Electrons Will Not Move Unless A Electrons Will Not Move Unless A Potential Difference ExistsPotential Difference Exists

VoltVolt

Creates The Potential DifferenceCreates The Potential Difference The Electromotive Force Which The Electromotive Force Which

Must Be Applied To Create Flow Of Must Be Applied To Create Flow Of ElectronsElectrons

Commercial Current Is 120 V or Commercial Current Is 120 V or 220 V220 V

ConductorsConductors

Materials That Permit Free Movement Materials That Permit Free Movement of Electrons of Electrons

Composed Of Large Numbers of Free Composed Of Large Numbers of Free ElectronsElectrons

Offer Little Resistance To Current FlowOffer Little Resistance To Current Flow Good ConductorsGood Conductors

• Metals (copper, gold, silver, aluminum)Metals (copper, gold, silver, aluminum)• Electrolyte SolutionsElectrolyte Solutions

InsulatorsInsulators

Materials That Resist The Flow Of Materials That Resist The Flow Of ElectronsElectrons

Contain Few Free ElectronsContain Few Free Electrons Insulator MaterialsInsulator Materials

• Air, Wood, GlassAir, Wood, Glass

Resistance = Electrical Resistance = Electrical ImpedanceImpedance

Opposition To Flow Of Electrical Opposition To Flow Of Electrical CurrentCurrent

Measured In OhmsMeasured In Ohms Ohm’s LawOhm’s Law Current Flow= Current Flow=

Voltage Voltage ResistanceResistance

WattWatt

Measure of Electrical PowerMeasure of Electrical Power Watts = Volts X AmpsWatts = Volts X Amps Modalities Use Milliamps or Modalities Use Milliamps or

MicroampsMicroamps

Electrotherapeutic Electrotherapeutic CurrentsCurrents

Direct (DC) or MonophasicDirect (DC) or Monophasic• Flow of Electrons Always In Same DirectionFlow of Electrons Always In Same Direction• Sometimes Called GalvanicSometimes Called Galvanic

Electrotherapeutic CurrentElectrotherapeutic Current

Alternating (AC) or BiphasicAlternating (AC) or Biphasic• Flow of Electrons Changes DirectionFlow of Electrons Changes Direction

– Always Flows From Negative to Positive Pole Until Always Flows From Negative to Positive Pole Until Polarity Is ReversedPolarity Is Reversed

Electrotherapeutic Electrotherapeutic CurrentsCurrents

Pulsed or PolyphasicPulsed or Polyphasic• Pulses Grouped Together and InterruptedPulses Grouped Together and Interrupted

– Russian and Interferential CurrentsRussian and Interferential Currents

Electrical GeneratorsElectrical Generators

All Are Transcutaneous Electrical All Are Transcutaneous Electrical StimulatorsStimulators• Transcutaneous Electrical Nerve Transcutaneous Electrical Nerve

Stimulators Stimulators (TENS)(TENS)• Neuromuscular Electrical Stimulator Neuromuscular Electrical Stimulator

(NMES)(NMES) = Electrical Muscle Stimulator = Electrical Muscle Stimulator (EMS)(EMS)

• Microcurrent Electrical Nerve Stimulators Microcurrent Electrical Nerve Stimulators (MENS) (MENS) = Low Intensity Stimulators = Low Intensity Stimulators (LIS)(LIS)

Electrotherapeutic Electrotherapeutic CurrentsCurrents

No Relationship Between Type Of No Relationship Between Type Of Current Used To Power Generator and Current Used To Power Generator and Type Of Current Output To PatientType Of Current Output To Patient

Generators May Be Powered By AC or Generators May Be Powered By AC or DCDC• Batteries = DC between 1.5 and 9 VBatteries = DC between 1.5 and 9 V• Wall Outlet = AC at 120 or 220V at 60 HzWall Outlet = AC at 120 or 220V at 60 Hz

Waveform or PulseWaveform or Pulse

Pulse= Individual Pulse= Individual WaveformWaveform

Phases (Duration)Phases (Duration) Interpulse IntervalInterpulse Interval Direction (Polarity)Direction (Polarity) AmplitudeAmplitude Rate Of RiseRate Of Rise Rate of DecayRate of Decay

• AccommodationAccommodation

Symmetrical WaveformsSymmetrical Waveforms

SineSine SquareSquare TriangulTriangul

arar

Symmetrical WaveformsSymmetrical Waveforms

Twin Peaked Twin Peaked Triangular Triangular WaveformWaveform• Found on Most High Found on Most High

Volt GeneratorsVolt Generators

Asymmetric WaveformsAsymmetric Waveforms

FaradicFaradic ExponentialExponential

• SawtoothSawtooth

Current ModulationCurrent Modulation

ContinuousContinuous InterruptedInterrupted BurstBurst

• PacketsPackets• Pulse TrainsPulse Trains• BeatsBeats

Ramped (Surge)Ramped (Surge)

Pulse AmplitudePulse Amplitude

Same As Intensity or VoltageSame As Intensity or Voltage Measured In Milliamps or MicrovoltsMeasured In Milliamps or Microvolts Average Current Determined By Average Current Determined By

Interpulse Interval Or Current DurationInterpulse Interval Or Current Duration

Pulse DurationPulse Duration

Length Of Time Current Is FlowingLength Of Time Current Is Flowing With Monophasic Current Phase Duration With Monophasic Current Phase Duration

Is the Same As Pulse DurationIs the Same As Pulse Duration With Biphasic Current Pulse Duration Is With Biphasic Current Pulse Duration Is

Determined By The Combined Phase Determined By The Combined Phase DurationsDurations

With Polyphasic Current The Combined With Polyphasic Current The Combined Pulse Duration And Interpulse Interval Is Pulse Duration And Interpulse Interval Is The Pulse PeriodThe Pulse Period

Pulse Frequency (CPS, Pulse Frequency (CPS, PPS, Hz) PPS, Hz)

Effects The Type Of Muscle ContractionEffects The Type Of Muscle Contraction Effects The Mechanism of Pain Effects The Mechanism of Pain

ModulationModulation

Electrical CircuitsElectrical Circuits

Path of Current From Power Source Path of Current From Power Source Through Various Components Back Through Various Components Back To GeneratorTo Generator

Power Source-Conducting Medium Power Source-Conducting Medium - Component Resistors - Component Resistors • Series CircuitSeries Circuit• Parallel CircuitParallel Circuit

Series CircuitSeries Circuit

One Path For Current To TakeOne Path For Current To Take Component Resistors Placed End To EndComponent Resistors Placed End To End Total Resistance = Sum of ResistancesTotal Resistance = Sum of Resistances Total Voltage = Sum of Voltage DecreasesTotal Voltage = Sum of Voltage Decreases

Parallel CircuitParallel Circuit

Component Resistors Placed Side to Side With Component Resistors Placed Side to Side With Ends ConnectedEnds Connected

Current Chooses Path With Least ResistanceCurrent Chooses Path With Least Resistance Resistors Have Lower Resistance But Higher Resistors Have Lower Resistance But Higher

Current Flow Than A Series CircuitCurrent Flow Than A Series Circuit

Current Flow Through Current Flow Through Biologic TissuesBiologic Tissues

Combination Of Both Series And Parallel Combination Of Both Series And Parallel CircuitsCircuits

Tissue Highest In Water And Ion Content Best Tissue Highest In Water And Ion Content Best Conductors - Blood, Nerve, Muscle, Tendon, Conductors - Blood, Nerve, Muscle, Tendon, Skin, Fat, BoneSkin, Fat, Bone

Safety In Using Electrical Safety In Using Electrical EquipmentEquipment

Ground Fault InterruptorsGround 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