Basic electricity Flashcards
(48 cards)
what is inductance
induced voltage which is opposite indirection to the applied voltage
what causes opposition to the flow of applied current in an AC circuit
inductive and capacitance reactance
what represents capacitance in AC circuits
a capacitor
what is the function of a capacitor
serves as a reservoir or storehouse for electricity
why should nickel-cadmium batteries and lead acid batteries not be stored or serviced in the same area
the electrolyte in the nickel-cadmium batteries is chemically opposite to the lead acid battery electrolyte and the fumes from lead acid batteries can contaminate the electrolyte in the nickel cadmium batteries
what does an electrical circuit consists of
a source of electrical pressure, resistance in the form of an energy consuming device and conductors in the form of wires to provide an electron flow
or a power source, conductors, a load, and a switch
what is the most important law applicable to the study of electricity
Ohms law
what are the elements of Ohms law
voltage, current and resistance
what unit is used to measure power in DC circuits
watt
how many watts equal one kilowatt
1000
what are the three types of DC electrical circuits
series, parallel, series-parallel
what current changes occur in DC circuit when the applied voltage is increased and the resistance remains constant
current increases
what could cause a nickel cadmium battery to fail to deliver its rated capacity
cell imbalance or faulty cell
what are the functions of the most multimeters
the indicate amperes, volts, and ohms
what is one advantage of AC circuits over DC circuits in aircraft
1) AC can be transmitted over long distances more readily and more economically than DC 2) space and weight can be saved 3) circuit breakers will operate satisfactorily at altitude 4) AC devices are smaller and simpler 5) most 24 volt aircraft systems have special equipment that requires a certain amount of 400 cycle AC current
define the term impedance
the total opposition to the flow of current in an electrical circuit
how many cells make up a lead acid battery rated at 24 volts
12 cells
what should be the specific gravity of the electrolyte in a fully charged lead acid battery
specific gravity between 1.275 and 1.300
what is the effect of temperature on specific gravity of the electrolyte when checking a lead acid battery
battery temperature changes electrolyte density only when greater than 90 degrees or less than 70 degrees
why is a specific gravity of the electrolyte in a nickel cadmium battery not acceptable to determine battery charge
the electrolyte specific battery does not change with the state of charge
how is Ohms law expressed as an equation
I=E/R or R=E/I or E=IxR
what is the most frequent cause of damage to solid state components and integrated circuits
electro-static discharge (ESD) from the human body due to careless handling
what is magnetism
the property of an object to attract certain metallic substances
what is the difference between permanent and temporary magnets
when an external magnetizing force is removed, permanent magnets retain their magnetism for an extended time whereas temporary magnets quickly lose most of their magnetism
