29
1 Basic Principles of Electricity

1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

Embed Size (px)

Citation preview

Page 1: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

1

Basic Principles of Electricity

Page 2: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

2

ElectromagneticSpectrum

Electrical Stimulating CurrentsElectrical Stimulating CurrentsCommercial Radio and TelevisionCommercial Radio and Television

Shortwave DiathermyShortwave DiathermyMicrowave DiathermyMicrowave Diathermy

InfrareInfrareddLASERLASER

Visible LightVisible Light

UltravioletUltraviolet

Ionizing RadiationIonizing Radiation

{{

LongestLongestWavelengthWavelength

ShortestShortestWavelengthWavelength

LowestLowestFrequencyFrequency

HighestHighestFrequencyFrequency

Page 3: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 4: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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)

Page 5: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

5

Electrical Potential Difference

• Difference In Concentration of Electrons Between Two Points

• Electrons Will Not Move Unless A Potential Difference Exists

Page 6: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 7: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 8: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

8

Insulators

• Materials That Resist The Flow Of Electrons

• Contain Few Free Electrons

• Insulator Materials– Air, Wood, Glass

Page 9: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

9

Resistance = Electrical Impedance

• Opposition To Flow Of Electrical Current

• Measured In Ohms

• Ohm’s Law Current Flow= Voltage Resistance

Page 10: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

10

Watt

• Measure of Electrical Power

• Watts = Volts X Amps

• Modalities Use Milliamps or Microamps

Page 11: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

11

Electrotherapeutic Currents

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

Page 12: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

12

Electrotherapeutic Current

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

• Always Flows From Negative to Positive Pole Until Polarity Is Reversed

Page 13: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

13

Electrotherapeutic Currents

• Pulsed or Polyphasic– Pulses Grouped Together and Interrupted

• Russian and Interferential Currents

Page 14: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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)

Page 15: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 16: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

16

Waveform or Pulse

• Pulse= Individual Waveform

• Phases (Duration)• Interpulse Interval• Direction (Polarity)• Amplitude• Rate Of Rise• Rate of Decay

– Accommodation

Page 17: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

17

Symmetrical Waveforms

• Sine• Square• Triangula

r

Page 18: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

18

Symmetrical Waveforms

• Twin Peaked Triangular Waveform– Found on Most High

Volt Generators

Page 19: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

19

Asymmetric Waveforms

• Faradic• Exponential

– Sawtooth

Page 20: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

20

Current Modulation

• Continuous• Interrupted• Burst

– Packets– Pulse Trains– Beats

• Ramped (Surge)

Page 21: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

21

Pulse Amplitude

• Same As Intensity or Voltage• Measured In Milliamps or Microvolts• Average Current Determined By Interpulse

Interval Or Current Duration

Page 22: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 23: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

23

Pulse Frequency (CPS, PPS, Hz)

• Effects The Type Of Muscle Contraction• Effects The Mechanism of Pain Modulation

Page 24: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 25: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 26: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 27: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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

Page 28: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

28

Safety In Using Electrical Equipment

Page 29: 1 Basic Principles of Electricity. 2 Electromagnetic Spectrum Electrical Stimulating Currents Commercial Radio and Television Shortwave Diathermy Microwave

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