Average Value
The sum of the instantaneous voltages in a half cycle wave shape divided by the number of instantaneous voltages. In a sine wave, it is equal to 0.637 times the peak voltage.
Analog meters
Analog meters are a multifunctional multimeter that operates based on electrical mechanical movement.
Autotransformer
A transformer with a single electric winding, which can be used as a step-down or step-up device; a transformer characterized by no electrical isolation between primary and secondary.
Admittance
The reciprocal of a circuit’s impedance, measured in Siemens.
Atom
The atom is made up of subatomic particles, the most important of which are the electrons and protons.
Ammeter
An Ammeter is a device used for the measurement of current in amperes (or even in smaller units like mA or μA).
American Wire Gauge (AWG)
The system of notation for measuring the size of conductors or wires.
Alternating Current
An electric current that periodically changes its direction, usually many times per second.
Air-Gap Power
It is the power transferred from the machine stator to the rotor across the air gap.
Aluminum conductor steel reinforced (ACSR)
ACSR is a composite conductor which is made up of an amalgamation of aluminum wires surrounding the steel.
Ampere’s law
The magnetic field strength, at any point in the neighborhood of a circuit in which there is a current i, is equal to the vector sum of the contributions from all the differential elements of the circuit. The contribution dH, caused by a current i in an element ds at a distance r from a point P is given by
$d\text{H}=\frac{r[\text{r}*\text{ds}]}{{{r}^{2}}}$
An-bn-cn or abc sequence
The order in which the successive members of the set reach their positive maximum values. Phase a is followed by phase b and then by phase c.
Apparent power
The product of the root-mean-square voltage and the root-mean-square current.
Armature Winding
The winding in which AC voltage is produced by relative motion with respect to a magnetic field.
Average power
The time average of the instantaneous power; the average being taken over one period.
Analog Signal
A signal with a varying voltage or current. A continuous set of values.
Auto Ranging
A term used to describe test equipment where the test equipment automatically adjusts the range to display the correct readout. For example, if you are measuring a voltage under 2 volts, you would select read voltage and the meter would automatically read the voltage and display the value.