190104A Flashcards
Electrical Theory
What is an element?
material made of only one kind of atom
What charge do:
protons
neutrons
electrons
have?
positive
neutral
negative
When an atom gains an electron, it will have a ____ charge?
negative charge
when an atom loses an electron, it will have a _____ charge?
positive charge
What are valence electrons?
electrons in the outermost orbit of the atom
What are conductors?
material that allow electricity to pass through them
what law state that opposite charges attract each other?
columns law
What is voltage?
pressure/force causes electrons to flow
What is voltage defined as?
difference in electrical potential between two points
other names for voltage?
potential difference
electromotive force
sources of voltage or emf?
electrostatic, electromagnetic induction, electrochemical, photoelectric
when is voltage induced in a conductor electromagnetically?
any time a conductor moves at an angle of 90 degrees to a magnetic field
What is current?
amount of electron flow
what is the conventional theory?
current flows form positive to negative
what is electron theory?
electrons flow from negative to positive
what is resistance?
opposition to electron flowha
what is a resistor?
a device used to offer resistance to electron flow
what determines resistance?
cross sectional area
length
material
temperature
how does a positive coefficient of resistance work?
temp increases, resistance increases
what is a thermistor?
resistor that changes resistance based on temperature
voltage and resistance determine?
current flow
if voltage increases, ______ increases
current flow
if resistance increases, current _____
decreases
What is DC?
current flowing in one direction
