Patient Mike Smith is still going through is Tommy John Rehabilitation with his Physical Therapist.  He has performed all of his rehabilitation processes for the first two weeks after surgery.  Up next for Mike is an appointment with his PT in which he will have electric stimulation on his joints and muscles surrounding his injured elbow.  The electric stimulation machine that the PT is using is a unique high-voltage direct current generator of 400 volts.  Find the resistance and current from this machine.

Givens:

2 Electrodes used:  1 will be placed on the lateral aspect of the elbow and the other will be placed on the medial aspect of the elbow.

Size of the electrodes: 8.5 cm x 8.5 cm

Electrode Separation:2.3 inches

Electrode thickness: ¼ inch

Voltage of machine: 400 V

Conversions needed:

Electrode separation: 2.3in =5.482cm

Electrode thickness: .25in =0.00635 m

Now we can find the Area of the electrodes:

8.5cm x 5.482cm= 46.597cm =0.466m^2

The next step of the problem requires common knowledge or research of skin, fat, muscle thickness (I found these online the resources are presented below the problem).

Skin thickness: .0095m

Fat thickness: .030m

Muscle thickness: 0.85m

Resistivity values: (Found on online Scholary sources)

P of skin= 750 Ω⋅m

p of fat=28Ω⋅m

p of muscle=13Ω⋅m

R of skin=(750Ω⋅m)*(0.0095m)/(.466 m^2)= 15.29Ω

R of fat=(28Ω⋅m)*(0.030m)/ (.466 m^2)= 1.80Ω

R of muscle=(13Ω⋅m)*(0.085m)/ (.466m^2)= 2.37Ω

Total Resistance of fat, skin, and muscle:  (15.29+1.80+2.37)=19.4Ω

This is the first step to the problem to determining the current produced.  In this first step I was able to find the total resistance of the circuit.  Being that we already know that this is a high-voltage direct current generator of 400 volts we can easily find the current with the formula: 

V=400

R=19.4

I= 400 V/ 19.4 Ω

I= 20.6 A