ABSTRACT
SI units represent an agreed international format used to standardise certain measurements. The term SI unit is an international system which contains certain base units and also what are known as derived units which are units that have combined one or more of the base units. Electrical current is measured in amperes sometimes shortened to amps. The metre was first used to define measurements but of course is also part of the metric system, which is the system of measurement used in science and engineering in most countries but not America. A derived unit uses one or more of the SI base units. A fuse is classified as a type of circuit protective device. A battery produces an emf through a chemical effect. The third effect produced when an electric current flows through a conductor is magnetism. An electromagnetic device only produces magnetism when an electric current flows through it.
