Define Electricity Answer- the flow of electrons
What are the 5 basic units of electricity? For each give what is measures? Answer- 1.
Coulomb- quantity of electrons
2. Amp- current
3. Volt- electrical pressure
4. Ohm- opposition
5. Watt- Power dissipated
Give the strict definition of a coul...
What are the 5 basic units of electricity? For each give what is measures? Answer- 1.
Coulomb- quantity of electrons
2. Amp- current
3. Volt- electrical pressure
4. Ohm- opposition
5. Watt- Power dissipated
Give the strict definition of a coulomb Answer- 6.28 x 10^18 electrons
Give the strict definition of an amp Answer- amount of coulombs passing a point in 1
second
Give the strict definition of a volt Answer- the electrical pressure it takes to move 1 amp
through 1 ohm.
Give the strict definition of a ohm Answer- the opposition that allows 1 amp to be moved
by 1 volt.
Give the strict definition of a watt Answer- the power dissipated by 1 amp moved
through 1 ohm by volt
What are the two basic methods of increasing the strength of the flux produced by an
electrical current? Answer- 1. Increase current (amps)
2. increase the flux density
What are the 3 elements any complete circuit? Answer- 1. Source
2. Conductor
3. Load
State Ohm's Law Answer- "The current in a circuit is directly proportional to the voltage
and is indirectly proportional to the opposition of circuit."
Give Ohm's Law mathematically (define all variables and give units) Answer- E= I/R or
I=E/R
I=current in amps
E= Voltage in volts
R= Resistance in ohms
, What is the purpose of a solenoid and a relay? Answer- They use a small amount of
current to control a large amount of current
What is the difference between a solenoid and relay? Answer- Relay- has a unmovable
core
Solenoid- has a movable core
What is the principle is AC generated? Answer- Electromagnet induction- a conductor is
moved through a flux field in such a way that it cuts through lines of flux, and a current
is induced into conductor through the constant movement of flux lines.
Define frequency Answer- the number of cycles per second
Define period Answer- how many seconds 1 cycle requires
What is the mathematical relationship between frequency and period? Answer- F=1/P
P=1/F
Discuss the difference between inductance and inductive reactance. Answer-
Inductance- opposition to change to current
Inductive reactance- opposition to current caused by inductance
Discuss the difference between total opposition to current flow in AC and DC Answer-
DC- total opposition to current flow is just the total resistance, measured in ohms
AC- combination of total resistance, total inductive reactance, total capactive reactance,
called impedance
Define a battery Answer- a device composed of two or more cells in which chemical
energy is converted into electrical energy.
Explain how batteries create voltage Answer- 1. each cell of a battery has two dissimilar
metals called electrodes and there is a solution separating called electrolyte.
2. One electrode is forced to give off a electron (becoming positive and known as the
anode) and the other receives it (becoming negative and known as the cathode). That
difference in charge creates the voltage.
Give 3 purpose of the primary battery in an aircraft application Answer- 1. Ground OPS
(Engine start-ups)
2. To absorb spikes of voltage from generators or alternator.
3. A "back up" voltage for emergency
What are the 2 batteries most widely used in aircraft application? Are they primary, or
secondary cells? Answer- Lead-acid
Ni-Cd
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