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

materials that permit the free movement of electrons, minimal opposition to current flow

(metals, electrolyte solution)

materials that resist current flow

(air, wood, rubber, glass)

current flow (l) = voltage / resistance (R)

a current with high resistance will have less flow

rate at which electrical power is being used, measurement of total electrical energy

watt = volts x amps

(Monophasic)

uninterrupted unidirectional flow of electrons, can change the polarity

[image] 

(Biphasic)

uninterrupted bidirectional, constantly changing, reversing polarity; terminators of the generator/source change from positive to negative

[image]

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)

intensity of the current (highest point of each phase)

AKA- peak amplitude

SAME AS VOLTAGE AND CURRENT INTENSITY

individual waveform, isolated electrical event separated by a finite (off time) period of time from the next event

(contains one or more phase)

unidirectional=monophase=known polarity=one phase/pulse

bidirectional=biphasic=2 separate phases/cycle

complete wave of an alternating current

(pulse applies to monophasic current)

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

different shapes for each phase

• balanced- the net charge in both directions is equal
• unbalanced- one phase has a greater net charge

(AC only)

same shape and size for each phase in both directions

(AC only!)

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

elapsed time from the initiation of 1 pulse to the start of the subsequent pulse

(Pulse duration + interpulse interval)= pulse period

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

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

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

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

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!!

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

• each channel split into 2 electrodes, all 4 applied over target tissue
• intersecting/interfering or parallel
• intensity from each set of electrodes adds together in order to increase intensity
• If superficial, pads should be closer together
• placement farther apart = greater depth of penetration and less specificity
• placed parallel with muscle fibers = greater conductivity

combined amplitude of 2 distinct circuits increases the amplitude

(if both waves originate at the same time, they combine)

combined amplitude of 2 distinct circuits decreases the amplitude

[if both waves are out of sync; one generator goes in one direction (positive) and the other goes in the opposite (negative) direction; the waves cancel out]