This slide is about sinusoidal current it's characteristics,how its works ,it contraindications and indications

2. Definition:
 A sinusoidal current is an evenly alternating
sine wave low frequency current with a
frequency of 50 HZ
 It can be produced from the mains by reducing
the voltage to 60-80 V with a step down
transformer.
 Patient feel tingling sensation
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Sine waves are characterized by the amplitude and
period. The amplitude is the maximum value of a
voltage or current; the period is the time interval for
one complete cycle.
Sine waves
0 V
10 V
-10 V
15 V
-15 V
-20 V
t ( s)

0 25 37.5 50.0
20 V
The amplitude (A) of
this sine wave is
20 V
The period is 50.0 s
A
T

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Characteristics of a Sine Wave
 The length of time it takes to complete one
cycle or conversely the number of cycles
that occur in one second.
 Period
 The maximum and minimum voltage or
current
 Amplitude

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Period, T
The period of a sine wave can be measured
between any two corresponding points on the
waveform.

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Frequency, f
3.0 Hz
Frequency ( f ) is the number of cycles that a sine
wave completes in one second.
Frequency is measured in hertz (Hz).
If 3 cycles of a wave occur in one second, the frequency is
1.0 s

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Amplitude, A
 Peak amplitude  Peak-to-Peak
amplitude
The amplitude of a sine wave is only measured from the center to
the maximum point.

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Sinusoidal voltages are produced by ac generators and
electronic oscillators.
Generation of a sine wave
N S
Motion of conductor Conductor
B
C
D
A
A
B
C
D
A
B
B
C
D
A
C
B
C
D
A
D
When a conductor rotates in a constant magnetic field, a
sinusoidal wave is generated.
B
C
D
A
B - When the loop is moving perpendicular
to the lines of flux, the maximum voltage is
induced

9. Tetanic muscle
contraction and tingling
sensation due to motor
& sensory nerve
stimulation
Rhythmic muscle
contraction helps in
edema reduction
Pain relief via sensory
stimulation by the same
mechanisms of TENS
Enhance blood flow and
intramuscular
Reduction of edema and
inflammatory
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10.  Burn:
a. Overdose( high intensity, long duration)
b. Bare metal electrode on the skin.
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11.  Shock:
Sudden Increase or decrease of the
current intensity.
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Current 11

12.  Sinusoidal current can be applied in the same
way as other low-frequency currents by
means of electrodes and pads.
 However, because of the marked sensory
stimulation this current is often applied to
large areas and rarely used for local muscle
stimulation.
 So it is applied through large pads
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For pain it can be used in continuous mode at intensities
close to the limit of tolerance and increase the current with
accommodation. Application will be done for 5 min and
repeated.
For reduction of oedema and to increase the limb
circulation sinusoidal current is suggested. causing regular
rhythmical muscle pumping actions.

14.  Put the patient in a comfortable position.
 Explain the patient the purpose of the
treatment.
 Select the setting on the machine for a
sinusoidal current with a pulse duration of 10
ms, and a frequency of 50 Hz.
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Current 14

15.  Connect the leads to the metal electrode and to
the machine.
 The pads should be moistened evenly.
 Explain the sensation to the patient “tingling
sensation”
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16.  Increase the intensity gradually till the patient
experiences tingling sensation under the
electrode. The response decreases slowly
after20-30 sec then increase the intensity
gradually.
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17.  Continue this. After 4 minutes see if the
tingling is adequate there is immediate
marked numbness to touch and pressure, and
all pain in the treated area is lost.
 If there is no numbness or partial, repeat for
4 min.
 The erythema and numbness persists for
about 1 h.
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Current 17

18. Thank u
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