I = E / R
where, I = current (unit -ampere), E = EMF(unit- Volt) and R = resistance (unit- ohm)
1 kilowatt is power consumed in one hour.
W = I × E
Battery: connecting a *primary cells (1.5 v) in series or parallel combination forms battery.
*primary cells cannot be recharged
Volt: The S.I.* unit of EMF. The Difference of potential that would carry one ampere of current
against one ohm resistance.
*SI UNITS: Système International d'Unités (INTERNATIONAL SYSTEM OF UNITS)
Ampere: It is a unit of current. one ampere of current represents one coulomb of electric charge
moving past a specific point in one second.
EMF: The rate at which energy is drawn from the source when unit current flows
through the circuit measured in unit, Volts.
* For aircraft requiring a battery of 12v, 6 cells are connected in series. When the cells are connected in
parallel, the voltage of the battery remains the same as the single cell. however, the amount of current
that can be drawn from the battery will multiply depending upon number of cells in parallel.
Resistance: The force that oppose the flow of electron current in a conductor.
unit of resistance is ohm.
Capacitance/capacitor: It is a passive electronic component that stores energy in a form
of an electrostatic field. unit of capacitance is farad.
Eddy Current: An electric current induced within the body of a conductor when conductor
either moves through a non-uniform magnetic magnetic field or in the region
where there is a change in magnetic flux. It is sometimes called Foucault current.
Eddy current cause heat and electromagnetic force in current.
Eddy current is superficial phenomenon.
Kirchhoff`s first law: The algebraic sum of current in network of conductors meeting at a point is zero.
In figure 1. given above, i1 + i4 = i2 + i3 (according to Kirchhoff circuit law)
Kirchhoff`s second law: The directed sum of the electronic potential differences
(voltage) around any close circuit is zero.
In figure 2. given above, V1 + V2 + V3 + V4 = 0
Formula to calculate electric fan RPM:
H.P. = (T ×N)/5252
H.P. - horse power
N= speed (RPM)
A choke is a coil of insulated wire often wound on a magnetic core, used as a passive inductor which blocks higher frequency A.C. in an electric circuit while allowing to pass low frequency and direct current by having an impedance largely determined by reactance.