notes Flashcards
Matter is composed of?
Atoms
Atoms are broken up into even smaller particles which are?
subatomic particles
what are the smallest particles that elements can be broken into and still retain properties of the element?
Atoms
Two subatomic particles are found within the nucleas?
Protons and neutrons
What is the heaviest part of the atom?
Nucleas
What is the third subatomic particles?
electrons
What does electrons do?
They are in motion around the nucleus and have negative charge.
Electrons occupy various energy levels around the nucleus known as?
Shells
The outer shell of the nucleus is called?
Valence shell
The number electrons that reside in the valence shell is determined by?
Conductors, Semiconductors and insulator.
Valence shells holds a maximum of?
Eight electrons
What is an insulator?
something through electricity cannot pass
What is a semiconductor?
a material that conducts current.
What is current?
flow of electricity through a conductor
Current is measured in?
Amperes
Ampere is defined as?
One Coulomb
The symbol used for amps is?
A
What is the basic unit of electrical charge?
Coulomb
What is current measured with?
Anmeter
What is pressure to an electron?
electromagnetic repulsion from a larger negative charge
What is electrical pressure measured in?
Volts
What is voltage also known for?
electrical potential difference & electromotive force
You measure volts with?
Voltmeter
What is resistance?
hinders of electric flow
Resistance is measured in?
Ohms
How is one ohm defined?
The amount of resistance that will allow one ampere of current to flow if one volt of electrical pressure is placed on a conductor
Resistance can be measured by?
a ohmeter
Current and resistance are?
inverserly proportional
Voltage and current are?
Directly proportional
What are the three most common things used as conductors?
Silver, copper and aluminium
What is the most expensive conductor?
Silver
What is conventional current?
flow of positive charge and is opposite in direction to actual electron flow.
What is a circuit?
A complete loop or path that electricity can follow
What are three essential components of an electrical circuit?
Voltage Source, Load, Conductors
What is a closed circuit?
Current can flow in an uninterrupted path
What is a load?
converts one type of electricity to another
What is a open circuit?
A circuit that is not complete
The relationship between voltage, current and resistance through a wire is called?
Ohms Law
What is the formula of Ohms Law?
V=IR
What does the I stand for in Ohms Law?
Current
What is a example of voltage source?
Batteries
What is a series circuit?
A circuit that has only one path for current to flow
What is a parallel circuit
voltage is the same throughout each parallel branch of the circuit, while current flow varies.
Most residential circuits are what kind?
Series-parallel
What is electrical power?
the actual rate at which energy is provided to and consumed by a electric circuit
What is power expressed in?
Watts
what is the power law equation?
P=IV
What is electricity?
flow of electrons through a conductor such as copper or aluminium wire
What is a conductor?
material through which electricity can pass
What is voltage?
strength which with current flows through a conductor
what is power?
The amount of energy transferred through a specify time
What is watts?
measure of electric power
Most things in your house requires how many volts?
120
What do you use to measure watts?
watt meter
What does AC Current stand for?
Alternating Current
What does DC Current stand for?
Directing Current
What direction does AC Current flow?
both direction
What direction does DC Current flow?
in one direction
A circiuit is?
A sys of connected conductors that direct the path of electricity.
What is a resistor?
Resists the flow of current and can change the amount of current that’s flowing through.
What is the diode?
allows electrical current to flow only in one direction
What is frequency?
A measurement of how many times a certain thing is done in a certain amount of time
What is frequency expressed in?
Hertz
What are waves measured in?
Wave lengths
What are some examples that work on DC?
Cell Phones, laptops, and electronic devices
What is a AC Current?
current that changes direction many times in a second as it moves in a conductor
What are some items that deliver AC Current?
HHousehold electrical outlets
How many hertz is AC delivered in?
60 hertz
What is hertz?
the frequency of the signal and how many complete cycles occur in 1 second.
What is the frequency equation?
f= 1/T
What is ground?
the lowest potential in a circuit
What wiring is common in residential wiring?
Ground Wiring to prevent electric shock
What is a resistor do?
A component used to limit current or voltage
What are the two types of resistors?
Fixed and variable.
What is a fixed resistor
fixed resistance
What is a variable resistor?
resistances that can be changed
What are potientiometers good for?
changing the voltage drop across a component in a circuit
What can potientionmeters good for?
adjusting the volume in a tv radio or stereo
What are two types of variable resistors?
rheostats and potientionmeters
Fixed resistors use a certain system to help determine resistance in ohms what is this called?
Color Band System
Fuses and Circuit breakers are very important too?
Circuits
How does a short circuit occurs?
a load is bypassed with a conductor
What are fuses?
Thin wires that melts when current exceeds a prescribed amount and preventing electricity flowing
What is one disadvantage of a fuse?
When it is blown it has to be replaced before the circuit works again
What is one advantage a circuit breaker has over a fuse?
Able to be reused multiple times
What are capacitors?
are electrical storage units
How are capacitors constructed?
Two metal conduction plates with a very thin insulator
A capacitors opposition to flow of current is called?
A capacitive reactance
Capacitance is represented by what letter symbol?
C
What two materials joined together create diodes?
P types and N types
What is a transistor?
a semiconductor device with three connections
What are the two types of transistors?
NPN & PNP
What is a NPN Transistor made up of?
thin piece of p-type material sandwiched between two pieces
What is PNP transistor made up of?
two pieces of p-type material that have a N-type material between them
What is the middle piece in a transistor called?
base
What is the two outside pieces called?
Collector & Emitter
How does a PNP Transistor works?
requires negative volatge at the base to turn on. Then current flows from the emitter to the collector
A diode only outputs?
DC Current
What are the positive charges?
Protons
What are the negative charges?
Electrons
What are some examples of EM Waves?
Light, Radio & X-Ray Waves
All EM Waves travel through a vacuum at the speed of light?
186,000 mph
Current is denoted by?
I
What are the best conductors?
Silver and Copper
Silver & Germainium are great examples of?
Semiconductors
Poor Conductors are also known as?
Insulators
What is impedance?
Anything that effects the flow of current
What is a particular kind of impedence?
Resistance
Electromagnetic waves travel through?
A vacuum
What is C means?
Capacitor
What is a fuse?
A circuit element that allows the flow of current below a certain value.