The document discusses galvanic currents, including a brief history where Luigi Galvani first showed that electric current caused frog legs to twitch. It defines direct current (DC) as electrical current that flows in one constant direction, as opposed to alternating current (AC) which reverses direction. The document describes modifications to DC including interrupted DC where current flows and ceases at regular intervals. It discusses waveform characteristics like duration and frequency, and different types of interrupted DC waveforms including rectangular, triangular, trapezoidal, saw tooth, and depolarized.

1. Galvanic CurrentsGalvanic Currents
Dr.Deepak Anap,Asso. Professor
COPT,PDVVPF
deepak.anap@hotmail.com
Galvanic Currents - Dr.Deepak

2. Objectives
• History
• Introduction to DC
• Graphical Representation
• Interrupted DC
• Wave form Characteristics – Duration and Frequency
• IDC Waveforms
Galvanic Currents - Dr.Deepak

3. History
• Luigi Galvani ,an Italian Physiologist-on whose
honor galvanic current is named.
• First to show that when electric current is passed
through the legs of a frog, it twitched, way back
in 1791.
Galvanic Currents - Dr.Deepak

4. Galvanic Currents - Dr.Deepak

5. Definition
• In DC, electrical current flows in one constant
direction, as opposed to AC, in which the current
constantly reverses direction.
• Ex of a device that provides DC : battery.
• DC ultimately supplies power to nearly all
electronic devices (even if these devices require a
component to convert AC current into DC
current).
Galvanic Currents - Dr.Deepak

6. DC Vs AC
Galvanic Currents - Dr.Deepak

7. Galvanic Currents - Dr.Deepak

8. Modifications of DC
• Interruption – most usual modification of DC
• Interrupted DC
• Current flow commencing & ceasing at
regular intervals
Galvanic Currents - Dr.Deepak

9. Wave form Characteristics
• Duration
• Duration 100,300,600ms used for Treatment
with IDC
Galvanic Currents - Dr.Deepak
Duration

10. • Frequency: No. of impulses/Sec
• Depends on duration of Interval between the
impulses
• Duration α 1/Frequency
Galvanic Currents - Dr.Deepak
Duration of interval

11. Galvanic Currents - Dr.Deepak

12. IDC waveforms
Galvanic Currents - Dr.Deepak
DC
Rectangular IDC
Current rises suddenly, constantly maintained for the
duration of the stimulus then turned off abruptly

13. Triangular Pulses
• Traingular: has an equal phase of slow rise
and then slow falling off in intensity
Galvanic Currents - Dr.Deepak

14. Trapezoidal Pulses
Current rises slowly, plateaus for a short
period then gradually declines
Galvanic Currents - Dr.Deepak

15. Saw Tooth Pulses
current is gradually raised then turned off
abruptly
Galvanic Currents - Dr.Deepak

16. Depolarised Wave Form
• Current of low intensity flows in reverse
direction
• Chemical formation because of DC is reduced
Galvanic Currents - Dr.Deepak

17. Thank you