2-7 Lol Flashcards
(39 cards)
Electric circuit consists of what 3 parts
Power source, conductors, load
What is a load
The device that uses electrical energy
What do switches do
Open and close circuits
The ____ of the voltage source determines direction of current flow, and the ______ of voltage determines hiw much current will flow
Polarity; amount
What two factors determine how much current flows in a dc circuit
Amount of source voltage, how well the load and wires conduct current
The ease with which a metal allows current to flow is described by the term
Conductance
The resistance of any material depends on
The number of free electrons the material has
In most cases, the resistance of the load is much _____ than the resistance of the circuit wiring
Greater
The property of maintaining a small tolerance under all operating conditions is called the ______ of the resistor
Stability
Resistor using three terminals
Potentiometer
Resistor using 2 terminals
Rheostat
When solving using Ohm’s law, a good practice is to think in terms of
Knowns and unknowns
The rate at which work is done
Power
Total power consumed is measured in
Kilowatt hours
1 kilovolt=
1000 volts
In a series circuit, the total power consumed iat equal to
The sum of the power used by each individual load
Most resistor failures result from
Heat genwyrated in the resistor by the current flow
Maximum value that the current ir voltage can reach (in ac current)
Amplitude or peak value
The effective value of a pure sine wave is ____ times the peak value
.707
The ____ of an ac current and its ____ determune the magnitude if the self-induced emf
Frequency; amplitude
The magnetic field holds all the energy it has taken from the circuit until the current
Begins decreasing
Conductors a re sometimes coiled to increase the number of flux lines cut by the conductor and this results in
A larger self induced emf
In a purely resistive circuit, the power factor equals 1.0 and so the
Apparent power= true power
In a purely inductive circuit, voltage ____ current
Leads
