Week 1 (chapter 1) Flashcards
what are the three key elements a circuit needs to be able to function?
voltage (source of electrical pressure)
conductor
load
conductors must form a _____ _______ for current to flow?
complete path
without a complete path, electrons are unable to flow through a conductor; this is known as?
an open circuit
if a load in the system is not present or has been bypassed, it is called a?
short circuit
what is designed as an intentionally weakened point in the circuit to burn open when current becomes excessive?
fuse
fuses are connected in _____ with a load so the circuit will open if current rating is exceeded
series
does a short circuit have high or low resistance?
low
fuses are designed to melt at ____ amperages than the conductor, thereby protecting it.
lower
what are the two basic types of circuits?
series and parallel
all circuits are either _____, ______ or __________?
series, parallel, or a combination of the two
what type of circuit only has ONE path for current to flow?
series
because there is only one path for current to flow in a series connected circuit, current is ________ at any point in the circuit.
constant (the same)
In what application would you commonly see a circuit wired in series?
lighting
parallel circuits have _______ paths for current to flow?
multiple
what is a combination circuit?
one wired in series AND parallel
anything connected directly across two points of different potential are _________?
in series
any conductor, including the human body, that is connected in series will have current pass through it unless?
there is enough resistance to prevent it.
line workers should never put them selves in what position, even with protective gear?
in series, between two points of different potential
a recloser is in line with the source so it has all the current passing through it. this is done so the recloser can ______ _____ ______ and open up to protect the circuit
sense excess(fault) current
when protection devices, such as reclosers or sectionalizers are connected in series with the line, they will have ______ __ _________ running through them.
all the current
in a series circuit, _____ will drop across each ________ that is connected in the circuit.
voltage/resistance
power lines are considered ___________ type circuits because the EQUIPMENT that is connected in series with the line; however, the LAYOUT of the circuit is predominately ____________?
combination/parallel
sub-transmission substations are _________ to the transmission line
parallel
parallel circuits are distinguished by the fact that the electrical values seen by the source are ?
dependent upon the individual loads
distribution sub-stations are ______ to the sub-transmission lines.
parallel
are customer circuits parallel or series?
parallel
for a customer circuit, the source is at the _____ _____ and the load is at all the ________?
meter panel/appliances
voltage in a parallel circuit remains constant, while the _________ changes at different points in the circuit
current
as devices are added to the line, current flow through the conductors will ______.
increase.
in a series circuit, resistance equals the ?
sum of all the resistors
when you see a test question with a value expressed in kVA, what does this represent?
watts (use the power quadrant in the energy wheel)
in a parallel circuit, the applied voltage is the same for all resistors. what is the voltage drop across EACH resistor?
equal to the applied voltage. (for instance, 120 volts from source and zero volts return. all voltage is used up per each resistor)
in a series circuit, how can you check to see if your voltage drops are calculated correctly?
the total voltage drops across all the resistors should equal the applied voltage from source.
three lights are on the same 24 volt circuit, the middle light is out and the other two are lit. what type of circuit is this?
parallel
a 24 volt circuit has three, 60 watt light bulbs wired in series. How much current is on the circuit?
answer = 7.5 amps
use ….. I = P/E
P = 180 (total power in watts on the circuit)
E = 24
I = 7.5 amps
*check answer by calculating voltage drop across each resistor using the amperage that was found, (E = P/I) then add all the voltages and compare to the source voltage! if they match you are correct.
