Exam 1 Flashcards
Electrical current
The flow of electrons from an electron source (through wire)
Resistor
A material opposes current flow
Capacitor
A device that stores electrical energy
Impedance
Opposition of biological tissues to the flow of electrical current
Direct current
Flow of current in one direction (negative or positive)
Alternating current
Flow of current first in one direction then in the other (bidirectional)
Monophasic
Synonymous with direct current
Biphasic
Synonymous with alternating current
Phase
Current flow in one direction
Phase duration
Time period from beginning to end of one phase (leave isoelectic line until it returns)
Interphase duration
Time between phases (interphase interval)
Phase rise time
Time of isoelectric line until max amplitude
Phase decay time
Time from maximum amplitude until back at isoelectric line
Phase duration
Equal to phase duration for DC current and 2X phase duration for AC current
Burst
Series of successive pulses or cycles over a period of time
Burst
Series of successive pulses or cycles over a period of time
Burst duration
Time between beginning of 1st and end of last cycle or pulse
Interburst duration
Time between two successive bursts
Beat
The resulting current waveform when 2 or more sinusoidal waves intersect (interfere) with each other
Frequency
Number of times per second that a pulse, cycle, burst or beat occurs
Amplitude
Magnitude of current relative to the isoelectric line measured in amperes. Usually in micro to miliamperes. Can be peak, peak to peak, average, or root mean square
Duty cycle
Ratio of on to off time expressed as a percentage
Ramp up
Time period where current amplitude is increasing from zero to maximum
Ramp down
Time period where current amplitude is decreasing from maximum to zero
Modulation
Changes in amplitude, pulse duration, pulse frequency, or a combination of these to prevent nerve acccommodation to stimulation
