EG1 CH.6 Flashcards
Explain the conservation of energy.
Energy can neither be created nor destroyed, it can only be converted (changed from one form to another)
Explain the law of charges.
Like charges repel, opposite charges attract
T or F: If a conductor is passed near a magnet, current will flow if a complete circuit exists.
True
T or F: The machine that converts mechanical motion into electrical energy does so by spinning a magnet inside a coil of wire.
True
What is polarity?
When the voltage causes the electrons to move away (positive) or towards (negative) the generating source.
What are the three factors that affect voltage strength?
Number of turns in the coil of wire, Strength of magnetic field, and speed at which the magnetic lines of flux pass through the coil.
What does it take for a generator to produce one volt of electricity?
A single conductor must pass through 100,000,000 lines of flux in one second.
T or F: If you increase the coils of a conductor, you will achieve a higher voltage without changing the speed or strength of the magnetic field.
True
What is a sine wave in regards to voltage?
The graphical representation of an AC circuit.
Explain what happens as a generator goes through one turn, in regards to Alternating Current.
At 1/4 turn, generator reaches max positive value. At 1/2 turn, generator reaches zero and no voltage is produced. At 3/4 turn, generator reaches max negative value. At 1 full turn, generator goes back to zero charge.
T or F: Voltage only exists on the line when there is a positive charge.
False, a voltage exists whenever there is either a positive or negative charge.
What is another name for a complete rotation of a generator?
cycle
What is frequency, in regards to wavelengths?
The number of cycles in one second that a generator produces.
What is frequency measured in?
Hertz (Hz)
What is the frequency of power in the US and Canada?
60 Hz
What is the equation to find the voltage along a sine wave?
E(inst)=E(max)*Sine(angle)
How often does voltage fall to zero in a cycle?
3
How is DC different than AC?
DC voltage is constant in its strength and polarity over time and has a continuous value.
What do we use to compare DC to AC voltage?
RMS or Effective Value
What does RMS stand for?
Root Mean Square
What is the formula to find RMS?
RMS=0.707*Peak(V)
What is the formula to find peak voltage?
Peak=1.414*RMS
What is the only type of load found on a DC circuit?
Resistive
What are the three types of load found on an AC circuit?
Resistive, Inductive, and Capacitive
What does the type of load tell us?
It tells us the relationship between voltage and current.
Explain phase angle relationship.
If voltage and current rise and fall together at the same time they are in phase. If voltage and current rise and fall at different times they are out of phase.
Under what load does AC circuits produce true power?
Resistive
