Ammeter Ammeter An ammeter (from Ampere Meter) is a measuring instrument used to measure the current in a circuit. Electric currents are measured in amperes (A), hence the name. Instruments used to measure smaller currents, in the milliampere or microampere range, are designated as "milliammeters" or "microammeters". Early ammeters were laboratory instruments which relied on the Earth's magnetic field for operation. By the late 19th century, improved instruments were designed which could be mounted in any position and allowed accurate measurements in electric power systems. It is generally represented by letter 'A' in a circle. Ammeters have very low resistance and
Electrical tape Electrical tape Electrical tape (or insulating tape) is a type of pressure-sensitive tape used to insulate electrical wires and other materials that conduct electricity. It can be made of many plastics, but vinyl is most popular, as it stretches well and gives an effective and long lasting insulation. Electrical tape for class H insulation is made of fiberglass cloth. A wide variety of electrical tapes is available; some for highly specialized purposes. "The primary tapes used in electrical applications are vinyl, rubber, mastic, and varnished cambric." Electricians generally use only black tape for insulation purposes. The other colors are used