The U.S. Navy offers enlistees a chance to serve in more than 60 different job fields. One of the largest job fields, or ratings, in the U.S. Navy is hospital corpsman, or Navy corpsman..
Cell voltage. The standard electrical potential of a cell can be determined by the use of a standard potential table for the two half cells involved. The first step is to identify the two metals reacting in the cell. Then one looks up the standard electrode potential, E0, in volts, for each of the two half reactions.
Chemistry determines the cell voltage (1.2V or 1.5V and there are others like Lithium at 3.0V), whether the battery is rechargeable, and how the voltage changes as the battery discharges i.e. at what voltage is the battery considered to be flat or fully charged. Switched mode power supplies. One more point.