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Basic Ohmmeter Use
10 questions By Tony R. Kuphaldt
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Question 10 of 10
Some ohmmeters have a range where the measurement is expressed in units of siemens (usually microsiemens, or μS). What is a “siemens,” and how does it relate to the unit of the “ohm”?
Reveal answerThe unit of the “siemens” is a measurement of conductance, the reciprocal of resistance:
G = 1 RWhere,
G = conductance, in siemens
R = resistance, in ohms
Challenge question: what was the old unit for conductance, prior to the siemens? You will find it makes more sense than siemens, just as the old metric unit of temperature (“centigrade”) makes more sense than the new unit (celsius).
Notes:Ask your students, “is 1 microsiemens equivalent to a large resistance or a small resistance?” Have them explain their answer, without using a calculator.
