Basic Electricity Flashcards
One kilowatt is equal to how many watts?
1000 watts
What law describes the most fundamental or basic relationships in an electrical circuit?
Ohm’s law.
What are the three elements of Ohm’s law?
Voltage, current and resistance.
How would you write Ohm’s law as an equation?
E = I x R, R = E/I, I = E/R.
If the resistance in a DC circuit remains the same but the voltage doubles, what happens to the amount of current flowing in a circuit?
It also doubles.
In DC circuits, what unit measures power?
Watts.
What three elements are required to form an electrical circuit?
A source of electrical energy, a load or resistance to use the electricity, and wires or conductors to connect the source to the load.
DC circuits can take one of three forms or types. What are they?
Series, parallel, and complex ( or series-parallel ).
A 24-volt lead-acid battery has how many cells?
Twelve.
A fully charged lead-acid battery has a specific gravity that varies between what two values?
1.275 and 1.300
You must apply a correction to the specific gravity reading of the electrolyte of a lead-acid battery when the temperature is outside of what two values?
Whenever the temperature is less than 70 degrees Fahrenheit or more than 90 degrees Fahrenheit.
What is the reason for having separate facilities for storing and serving nickel-cadmium and lead-acid batteries?
The electrolyte in the two types of batteries is chemically opposite and the fumes from one type can contaminate the electrolyte of the other type.
The state of charge of a nickel-cadmium battery cannot be determined by measuring the specific gravity of the electrolyte for what reason?
There is no significant change in the specific gravity of the electrolyte as the battery is charged or discharged.
What is the principal advantage of AC current over DC current?
Power can be transmitted over long distances more efficiently and with smaller wires because the voltage can be easily increased or decreased by a transformer.
What are the three causes of opposition to current flow in an AC circuit?
Resistance, inductive reactance, and capacitive reactance.