Electrical Flashcards
What is the force exerted by protons and electrons?
Electric charge
What is the charge for Protons Electrons Neutrons
Positive Negative No charge
What are the four distinct states of matter?
Solid, liquid, gas, plasma
If an object has more protons than electrons, what is its electrical charge?
It is positively charged.
What are free electrons?
They are electrons that loosely bonded around the nucleus, and can be easily knocked loose
What is a molecule?
The smallest part that matter can be divided into, without changing its makeup.
Describe static electricity
When the positive and negative charges are balanced and the charge does not move
Describe unbalanced electrical charges
Unbalanced electrical charges is also known as electrical flow, or current flow. The greater the unbalance, the greater the voltage
What is magnetism?
It is the physical phenomenon caused by electron movement.
Describe a permanent magnet
The magnetic property is caused by the spinning of electrons in the atoms that make up the material the magnet is formed out of.
Describe an electromagnet
Caused by electrons moving through a coil of wire wound around a core material
How are magnetic fields pictured?
They are pictured as magnetic flux lines.
What are some common materials for permanent magnets?
Steel alloys, cobalt, nickel, alnico, platinum and cobalt alloys, samarium and cobalt alloys
What does a compass do near a wire carrying an electric charge?
It causes the needle to deflect at a right angle to the wire.
What are the basic principles of electromagnetism?
-moving electrically charged particles creates magnetic fields -magnetic fields attract or repel moving charged particles -moving magnetic fields near charged particles causes current flow
What does passing a magnetic field through a conductor generate?
Induced electromotive force(voltage). The current that is caused to flow is called induced current.
What is permeability in regards to electromagnets?
The ease in which a material can be magnetized by a solenoid.
What is a good conductor?
A material that exhibits low resistance to current flow
Give some examples of good conductors
Silver-best Copper-second Gold-third, but only one that resists oxidation
What makes a good insulator?
A material that is a poor conductor of electricity. Some examples are glass, mica, dry wood, plastics
What is a semiconductor?
A material that is neither a good conductor nor a good insulator.
Describe direct current (DC)
The flow of free electrons in the conductors is always in the same direction, and has fixed polarity.
What is ohms law formula?
E=IxR
What is E in formula?
E=power=volts=potential difference
What is I in formula?
I=current flow=amps
What is R in formula?
R=resistance=ohms
Changing AC to DC voltage is done with what
Rectifier
What is our RMS, and what is the value of it?
Root mean square, and its value is .707
What is the pattern of a single phase in one cycle?
Sine wave
How is voltage induced?
It is done when a conductor cuts magnetic lines of flux. The maximum induced voltage occurs when the conductor is traveling at right angles through the lines of flux
What is frequency?
Frequency is the number of cycles and alternating current generates for second also known as hertz
What is the sine wave form for a three-phase motors?
The phases are out of phase by 120°
How was DC voltage changed to AC?
Through an inverter
How does an electric current flow?
There must be a potential difference between two points of the supplying device the potential difference is called voltage measured in volts
What are amps?
Amps are the rate of flow of electrons in an electrical circuit
How many watts in 1 hp?
746 Watts
Describe an open circuit
It is a circuit that has an incomplete pass for current flow because a switch is open
Materials fall into one of three categories based on the resistance to current flow of that material. What are the three categories
Conductors, insulators, semi conductors
Describe electromotive force
The voltage generated by moving a conductor through a magnetic field
Describe resistance
The property of the materials that opposes the flow of an electric current
List three factors that determine the amount of voltage induced in a coil
Material of the coils core, frequency, amp turns
List four factors that affect the resistance of a conductor
-material -cross-sectional area -length of conductor -temperature
What does alternating current mean?
When the current changes polarity continuously and regularly
If an atom has more protons and electrons it is said to have what kind of a charge?
A positive charge
A metal that can be easily magnetized by solenoid is said to have what?
High permeability
When a conductor is passed through a magnetic field what is created?
Induced current
A material whose Atoms have free electrons in its outer valence is said to be what?
A good conductor
Current that flows from a positive to negative is called what
Conventional flow
In the series circuit what stays constant throughout?
The current or amps
What color is the grounded circuit conductor, or neutral wire in residential wiring
White
What is the wiring color combination for industrial three phase?
Black, red, blue
What is the amp a measure of?
Electron flow
What does a fuse protect the circuit from?
Over current
Voltage in a parallel circuit is?
Equal through each branch of the circuit
Is voltage measured in series or parallel with the load?
In parallel with the load
Time delay fuses have what?
Dual elements
