# Shared Flashcard Set

## Details

EXAM 2
Principles of Electricity, Application/Set up of E-Stim
41
Anatomy
03/18/2013

Term
 electron
Definition
 particles of matter possessing a negative electrical charge
Term
 ampere (A)
Definition
 rate at which electrical current is flowing
Term
 polarity
Definition
 positive and negative poles
Term
 volt/voltage
Definition
 1 volt = potential difference required to move 1 coulomb or charge   voltage: force resulting from an accumulation of electrons at 1 point in an electrical circuit
Term
 conductor
Definition
 materials that permit the free movement of electrons, minimal opposition to current flow (metals, electrolyte solution)
Term
 insulator
Definition
 materials that resist current flow (air, wood, rubber, glass)
Term
 Ohm
Definition
 measure of resistance
Term
 electrical impedance
Definition
 the opposition to electron flow in an insulator
Term
 Ohm's Law
Definition
 current flow (l) = voltage / resistance (R) a current with high resistance will have less flow
Term
 Watt
Definition
 rate at which electrical power is being used, measurement of total electrical energy watt = volts x amps
Term
 direct current
Definition
 (Monophasic) uninterrupted unidirectional flow of electrons, can change the polarity [image]
Term
 alternating current
Definition
 (Biphasic) uninterrupted bidirectional, constantly changing, reversing polarity; terminators of the generator/source change from positive to negative [image]
Term
 pulsatile current
Definition
 interrupted for short periods of time with no electron flow, series of pulses of shor duration Can be unidirectional or bidirecional monophasic- similar to DC (unidirectional - either +/-) with periods of non current flow biphasic- similar to AC (bidirectional- +/-) with periods of non current flow [image]  <----monophasic [image]<---- biphasic (symmetrical vs. asymmetrical)
Term
 frequency
Definition
 # of pulses per second
Term
 waveform
Definition
 graphic representation of shape, direction, amplitude, duration, and pulse frequency of current
Term
 amplitude
Definition
 intensity of the current (highest point of each phase) AKA- peak amplitude SAME AS VOLTAGE AND CURRENT INTENSITY
Term
 pulse
Definition
 individual waveform, isolated electrical event separated by a finite (off time) period of time from the next event (contains one or more phase)
Term
 phase
Definition
 unidirectional=monophase=known polarity=one phase/pulse   bidirectional=biphasic=2 separate phases/cycle
Term
 cycle
Definition
 complete wave of an alternating current (pulse applies to monophasic current)
Term
 pulse duration
Definition
 length if time current is flowing in one cycle, aka pulse width, beginning of the phase to the conclusion of the final phase (or time that each pulse lasts) monophasic: pulse duration equals phase duration biphasic: combined phase duration equals pulse duration pulsatile: pulse duration is determined by the combined phase durations and interphase interval sum of phases + interphase interval = pulse duration
Term
 phase duration
Definition
 time that each phase lasts
Term
 cycle duration
Definition
 same as pulse duration but for AC current only
Term
 interphase interval
Definition
 interruption betweeen individual phases (off time)
Term
 interpulse interval
Definition
 period of time between individual pulses, short period of time without current
Term
 rate of rise
Definition
 how quickly a waveform reaches its maximum amplitude
Term
 rise time
Definition
 time required for a  waveform to go from zero to peak amplitude
Term
 decay time
Definition
 time required from a waveform to go from peak amplitude to zero
Term
 asymmetrical current
Definition
 different shapes for each phase balanced- the net charge in both directions is equal unbalanced- one phase has a greater net charge (AC only)
Term
 Symmetrical
Definition
 same shape and size for each phase in both directions   (AC only!)
Term
 pulse charge
Definition
 total amount of electricity being delivered to the patient during each pulse, total # of electrons within a pulse monophasic current: pulse charge and phase charge are always the same and always > 0 biphasic: pulse charge is equal to the sum of the phase charges if pulse is symmetric, net pulse charge = 0 if pulse is asymmetric, net pulse is >or< 0
Term
 pulse period
Definition
 elapsed time from the initiation of 1 pulse to the start of the subsequent pulse   (Pulse duration + interpulse interval)= pulse period
Term
 modulation
Definition
 alteration in the amplitude, duration, frequency of the current
Term
 burst modulation
Definition
 occurs when pulsatile or biphasic current flows for a short duration and then is stopped for a short time in a repetitive cycle bursts: combined set of 3 or more pulses
Term
 beat modulation
Definition
 produced when 2 interfering biphasic current waveforms with differing frequencies are delivered to 2 separate pairs of electrodes through separate channels within the same generator   2 PAIRS OF ELECTRODES IN CRISSCROSSED PATTERN SO THE CIRCUITS INTERFERE WITH ONE ANOTHER
Term
 ramping/surging modulation
Definition
 current builds up gradually to maximum (preset) amplitude, used to elicit a muscle contraction, very comfortable type of current due to gradual increase in intensity of contraction   EX: russian
Term
 current density
Definition
 amount of current flow per cubic volume must be high enough to cause depolarization highest where electrodes meet the skin, decreases with skin penetration - difficult with fat layers
Term
 monopolar electrode
Definition
 electrodes of 2 different sizes ACTIVE ELECTRODE: placed where the treatment effect occurs DISPERSIVE ELECTRODE: completes the circuit; fastened to a body part at a distant location dispersiive pad has much larger surface area with little or no stimulation/current density COMBO!!
Term
 bipolar electrode
Definition
 2 electrodes of the same size both electrodes from single channel are placed over the target area both electrodes are same size (no dispersive pad) - should have equal stimulation at each electrode current is limited to target tissue PRE-MOD, RUSSIAN WITH TWO PADS
Term