General: Electricity Flashcards
(26 cards)
What constitues a capacitor?
Two conductiors seperated byan insulator.
What is the purpse of a capacitor?
It stores electrical energy in electro static fields.
Does a Capacitor in an AC circuit cause the cureent to lead or lag the voltage?
It causes the current to lead the voltage.
What is the basic unit of capacitance?
The Farad.
Why should electrolytic capacitors not be used in an AC circuit?
Because they are polarized. An electrolytic capacitor will pass current of one polarity but will block current the opposite polarity.
What is ment by inductance?
The ability to store elecrical endergy in electromagentic fields.
What is the basic unit of inductance?
The Henry.
What is an example of an inductor in a magneto?
The Coil.
Does the inductor in an AC circuit cause the cureent to lead or lag the voltage?
It causes the current to lag behind the voltage.
How can you find the polarity of an electromagnet?
Hold the magent in your left hand encicriling the coil in the direction electrons flow (from negative to positive). Your thumb will point to the north pole of the electromagnet.
What is meant by impedence?
The total opposition the flow of Alternateing Current. It is the vectorsum of resistance, capacitve reactance, and inductive reactance.
In what unit is impedence measured?
In ohms.
What are the five sources of electrical energy?
Magnatesim, Chemical Energy, Light, Heat, and preassure.
What is the basic unit of power in a DC circuit?
The watt.
What is meant by a killowatt?
1,000,000 watts.
What is meant by a megawatt?
1,000,000watts.
What is the formula for power in a DC circuit?
P=IE
What is the relationship between electrical power and mechanical power?
1 Horsepower=746 watts
What is meant by true power in an AC circuit?
The product of the circuit voltage and the current that is in phase with this voltage.
In what unit is true power expressed?
In watts.
What is meant by apparent power in an AC circuit?
The product of the circuit voltage with the circuit current.
In what units is apparent power expresssed?
In volt-amps.
What is meant by reactive power in an AC circuit?
the power consumed in the inductive and capacitve reactance in an AC circuit. Reactive power is called watt-less power.
In What units is reactive power expressed?
In volt-amps reactive (KVAR).
