Electronics Information Flashcards
Alternating current is so called because
the current changes direction many times per second
An electric current is
a form of energy
a flow of electrons
A battery
always produces a direct current
In a series circuit, total voltage drop equals
the sum of the individual voltage drops
A volt is a unit of electric(al)
pressure
The transformor depends on the relationsip between electricty and
magnetism
In an electric motor, magnets
repel each other
A circuit without resistance is called
a short circuit
A transformer changes the _______ in a circuit
current and voltage
In a series circuit, a switch controls
all devices on the circuit
Which is the same at all points in a parallel circuit
voltage
A switch in a series-parallel circuit controls
some or all devices
The purpose of dopant in a semiconductor is to make it act as a(n)
insulator or conductory
Electricity
a form of energy that can travel invisibly
Tiny negative charges that orbit the nucleus of an action
electrons
Conductor
a material that allows an easy flow of electrons
Good conductors
silver
copper
aluminum
Material that resists the flow of electrons
insulator
Good insulators
rubber
plastic
ceramic
A loop of conductor that tkes electricity from it’s source to the load and back to the source
circuit
Load
anything in the circuit such as a heater, a light, or motor that uses power
Direrct current (DC)
a steady flowiwng type of electricity produced by batteries and used in flashlights, boom boxes and computers
Alternating Current (AC)
type of current that changes direction many times per second (used in homes)
A branch of science that deals with complicated uses of electricity, such as radios, televisions, and computers
electronics
Electric current
the amount of electrons flowing through a conducting material
Amount of power consumed by an electrical device
electric power
Voltage
force that afects the rate at which electricity flows through a conductor
Sometimes called electrical pressure
voltage
Tells how much electrical pressure is used in a part fo the circuit
voltage drop
Frequency
the number of complete alternations-from one direction to the other and then back again-that alternating current makes per second
The opposition of a material to the flow of electricity through it
resistance
If a circuit does not have resistance, wires can overheat, this is called
a short circuit
Ohm’s law
describes the relationship among electircal pressure (voltage) current strength (amperage) and resistance (ohm’s) in any circuit
Amperes =
volts/ohms
Volts =
amperes x ohms
Ohms =
volts/amperes
Electric power
watts = volts x amperes
Amperes =
watts/volts
If a transformer has more turns of wire on the output side it is a
step up transformer
In a stepdown transformer
there are more turns on the input side and the output voltage is smaller than the input voltage
The same machines operating backwards
motors and generators
Changes rotating energy (kinetic) into electric energy
a generator
Motor
changes electric energy into kinetic energy
What drives a motor
the changes in polarity
The two types of magnets in a motor
rotor and stator
Spins inside the stator
Rotor (usually an electromagnet)
Stator
stationary magnet
In motors which poles attract
opposite, north attracts south but repels north
A device that can briefly store electricity
a capacitor
A resistor
creates resistance to the flow of electrons
If a circuit does not have any resisitance it is called
a short circuit
Changes the voltage and amperage of a current
a transformer
Transformers work by
changing electricity into magnetism, then back into electricity
How many coils does a transformer have
2
Stores electricty as chemical energy that can be readily converted into electric current
a battery
Batteris can be wet (like car batteries) or dry (like flashlight batteries)
Batteris can be wet (like car batteries) or dry (like flashlight batteries)
Always make Direct current (DC)
batteries
Some batteries can be recharged depending on
their chemistry
What travels through a circut to make an electric current
electro chemiclal reactions between the cathode and the carbon electrode at the center, resulting in free electrons
Exists only when electon can flow through a circuit
electric current
What are the types of circuits
series circuits
parallel circuits
All moving electrons pass through every part of the circuit including all the loads and swithches is a
series circuit
The quality of electrons
current
Is the same at all points of the circuit
current
Drops a sthe current goes through each device
voltage
The total voltage of the loads must equal the voltage of the
circuit
The loads are placed between the two supply wires so that they all get teh same voltage in a
parallel circuit
A switch controls the current in the entire circuit in a
Series circuit
Current can flow through only loads even if one is switched off in a
parallel circuit
Current is the same at all points in a
series circuit
Voltage is the same at all points in a
parallel circuit
How do you find total resistance in a series circuit
add teh resisitance of each load
To calculate the total resistance in a parallela circuit you
add the inveres of the reisitance
Combines features of series and parallel circuits
series-parallel circuit
The branch circuits that bring electric power to the lights and outlets are
series-parallel
Can act as a conductor or as an insulator
semiconductor
The main semiconductor that is the basis for computer memory and logic boards
silicon
Applied to silicon to determin whether it will act as an insulator or as a conductor by making electons available or not available to flow
dopants
When electrons can flow, a material becomes a
conductor
The basis for computer applications is a group of components called
transistors and diodes
Transistors
devices that can switch a current, regulate its flow, or amplify a current, all based on the prescence of a smaller current
Devices that allow a current to flow in one direction only
diodes
Diodes are also used in devices that convert AC into DC. These devices are called
rectifiers
Breaking up the load in the building into a number of circuits is a function of the
circuit breaker box
The circuit breaker box
prevents excess current from flowign into the circuits
breaks up the load in the building into a number of circuits
Simple circuits have what two separate conductors
hot and grounded
The hot conductor can be another color but it is usually
black
The grounded (sometimes called neutral) conductor is
white
Black and white wires together are called
supply wires
circuits can be shut off by
the fuses and circuit breakers
Home wiring systems are usually rated
15 or 20 amperes
15 ampere circuits require
14 gauge wires
Larger 12 gauge wires are required for
20 ampere circuits
Always wants to complete a circuit
electricity
Two options for returning current to the circuit breaker or fuse box are
white wire (grounded) is the normal path bare wire (equipment grounding) is the alternate path of something goes wrong with the grounded wire
Conduit
steel sheath or wires that protect bare wire
Brings current
black wire
Drains current away
white wire
Electric plugs that can fit into the socket in only one way because one lug on the plug is bigger than the other is called a
polarized plug
Turns electic circuits on and off
switches
One single-pole switch controls a circuit
One single-pole switch controls a circuit
Two three-way switches can work together to control a circuit from either fo two locations
such as at the top and bottom of a stairs
Continuously controls the voltage, and is used to dim lights
a rheostat
In home wiring switches alwasy control the hot side of the circuit
(the one that supplies the current)
If electrical connections are not secure and tight what will develop causing heat and ruining the connection
arcs will develop
Solder
a connection where metal is melted over a connection
Flux
a chemical that prevents oxidation from happening when wires get heated
Breaks the circuit (cuttng off the power) when something goes wrong is the job of the
circuit breakers and fuses
Usually has an electomagnet that opens a circuit when the current gets too high
a circuit breaker
Has an element that melts when the current is too high
fuse
Can be reset after they trip
circuit breakers
Coaxial
having the same axis
Cables that have an inner and outer conductor and are usually used in cable TV systems are called
coaxial cables