Question | Answer |
electrical current | movement of flow of charged particles through a conductor in response to applied electrical field
measured in amperes (A) |
charge | basic property of matter
noted as Q
measured in Coulombs (C) |
polarity | property of having 2 oppositely charged conductors |
voltage | electrical force capable of moving charged particles through a conductor between 2 regions
measured in Volts (V)
aka = Potential Difference |
resistance | Property of a conductor that resists, or is in opposition to the flow of charged particles.
Resistance (R) is measured in Ohms Ώ |
Ohm's Law | V = I x R
Voltage = Icurrent x Resistance |
impedance | The total frequency-dependent opposition to current flow.
Impedance (Z) is measured in Ohms.
For biological systems, Z describes the ratio of V to I more accurately than R because it is a frequency-dependent measure that includes capacitance and R. |
Direct Current | continuous unidirectional flow of charged particles
(DC) |
Alternating Current | Alternating Current (AC) is a continuous bi-directional flow of charged particles
AC has equal ion flow in each direction resulting in no net charge accumulation
Wave length is one cycle
↑ frequency = ↓ cycle duration |
Pulsed Current | Discontinuous in a series of pulses which may be uni- or bidirectional
[flow of charge is interrupted to create periods when no current flows] |
monophasic pulsed current | A series of unidirectional pulses.
A net charge results. |
biphasic current | may be symmetrical or asymmetrical
may be balanced or unbalanced |
Interferential Current | Waveform is produced by interference of two medium frequency sinusoidal AC of slightly different frequencies.
Uses 2 channels, 4 electrodes, placed so AC currents intersect and interfere. |
intensity | aka = strength, power, or amplitude |