IT’S THE LAW
OHM’S LAW IN THE WIRELESS WORLD FOR THOSE OF US WHO HAVE STOOD IN FRONT OF A CLASS OF KEEN PRE-APPRENTICES OR FIRST YEAR APPRENTICES, THE LOOK OF SHEER HORROR THAT WASHES OVER STUDENTS’ FACES AS YOU DRAW A FORMULA THAT INCLUDES LETTERS, FOLLOWED BY A SOLUTION THAT INCLUDES GREEK SYMBOLS WHEN YOU SOLVE IT, NEVER GETS OLD. The old refrain, ‘when will I ever need algebra’ suddenly becomes a regretful choice of statement! Yet without Ohm’s Law, our industry likely wouldn’t exist as it does today. When Alessandro Volta proposed that electricity wasn’t some ‘Star Wars’ type force in living beings, and went about proving it by inventing the battery, he set in motion the work of Georg Ohm. Ohm understood that a mathematical application could be applied to determine the current flowing in an electrical circuit. In his ground-breaking paper, Die Galvanische Kette, Mathematisch Bearbeitet, Ohm proved mathematically that a directly proportional relationship existed between voltage and resistance and their impact on current flow. This fundamental of electrotechnology theory provides a basis for many of the calculations used by electricians, technicians and engineers. For an electrician, Ohm’s Law is what Einstein’s Law of Relativity is to a physicist. The simple equation allows us to calculate an unknown value, if the two other variables are known. Whether voltage, current or resistance, any given two can be used to calculate the unknown quantity. For many apprentices, their
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first experience in electrical theory is based on calculating and then measuring volts, amps and ohms. As they finish their apprenticeship, the
Capstone Assessment draws on those fundamental relationships, from the design, to testing and fault finding.
June 2021
