Question

What is galvanic and faradic current ?

Answer 1

Galvanic and faradic current, both of them are direct current or we can say DC current, the main difference between the two are the difference in their range of frequency and their pulse range. As to say, Faradic current has a frequency range of $50\,to\,100Hz$ and its pulse duration is from $0.1 - 1{\text{ }}ms$ where as the galvanic current has frequency of $30{\text{ }}Hz$ and pulse duration of $1{\text{ }}ms$ and more.

Complete step by step answer:
Faradic current is said to be a short duration and interrupted form of direct current having pulse duration of $0.1{\text{ }}to{\text{ }}1{\text{ }}ms$ and frequency ranging from $50{\text{ }}to{\text{ }}100{\text{ }}Hz$. A galvanic type current is said to be a long duration and interrupted form of direct current having pulse duration of $1{\text{ }}ms$ and more and frequency $30{\text{ }}Hz$. Both Faradic as well as the galvanic current are used in electrotherapy, which uses low-frequency impulse current with low voltage.

Faradic waveforms are of below kind:
-Trapezoidal surging; a waveform where the impulse increases gradually followed by a gradual decrease.
-Triangular surging; a waveform where impulse forms trapezoidal surging.
-Saw tooth surging; a waveform which includes the gradual increase but sudden fall of impulse.

Galvanic waveforms are as follows:
-Rectangular surging; this waveform is achieved when the current is turned on and off abruptly.
-Trapezoidal surging; a waveform where there is a slow rise and slow fall.
-Triangular surging; a waveform where it raises slowly, plateaus and then falls slowly.
-Saw tooth surging; a waveform which includes the gradual increase but sudden fall of impulse.

Note: As both of the currents are used in the therapeutic process, we should understand that the physiological effect of faradic and galvanic currents is almost the same except the fact that the faradic is used for innervated muscle and galvanic is used for denervated muscle. Both the current increases the blood flow to the area of treatment that makes the area slightly red in appearance. Also, both the current leads to the contraction of muscle in the similar way the voluntary muscle contracts.