Fundamentals of Electricity and Electronics

Question 1

What is the difference between the conventional current flow theory and electron flow? (AM.I.A.K1)

Answer 1

Conventional current flow theory is a visualization of current as flowing from positive to negative. In actual practice, electrons in a current flow from negative to positive. (Electron theory)

Question 2

How can you find the polarity of an electromagnet? (AM.I.A.K2)

Answer 2

Hold the electromagnet in your left hand with your fingers encircling the coil in the direction electrons flow (from negative to positive). Your thumb will point to the north pole of the electromagnet.

Question 3

What constitutes a capacitor? (AM.I.A.K3)

Answer 3

Two conductors separated by an insulator.

Question 4

What is the purpose of a capacitor? (AM.I.A.K3)

Answer 4

It stores electrical energy in electrostatic fields.

Question 5

What is the basic unit of capacitance? (AM.I.A.K3)

Answer 5

The farad.

Question 6

Why should electrolytic capacitors not be used in an AC circuit? (AM.I.A.K3)

Answer 6

They are polarized. An electrolytic capacitor will pass current of one polarity, but will block current of the opposite polarity.

Question 7

What is meant by inductance? (AM.I.A.K4)

Answer 7

The ability to store electrical energy in electromagnetic fields.

Question 8

What is the basic unit of inductance? (AM.I.A.K4)

Answer 8

The henry.

Question 9

Given the inductance and the frequency of the AC in a circuit, how do you compute the inductive reactance caused by the coil? (AM.I.A.K4)

Answer 9

XL = (2)(pi)(f)(L), where XL = inductive reactance in ohms, f = frequency in cycles per second, pi = 3.1416, L = inductance.

Question 10

Does a capacitor in an AC circuit cause the current to lead or lag the voltage? (AM.I.A.K5)

Answer 10

It causes the current to lead the voltage.

Question 11

Does an inductor in an AC circuit cause the current to lead or lag the voltage? (AM.I.A.K5)

Answer 11

It causes the current to lag behind the voltage.

Question 12

What is the basic unit of power in a DC circuit? (AM.I.A.K6)

Answer 12

The watt.

Question 13

What happens to the current in a DC circuit if the voltage is increased by the resistance stays the same? (AM.I.A.K6)

Answer 13

It increases.

Question 14

What are five sources of electrical energy? (AM.I.A.K7)

Answer 14

Magnetism, chemical energy, light, heat, and pressure.

Question 15

Which law of electricity is the most important for an aircraft mechanic to know? (AM.I.A.K7)

Answer 15

Ohm’s Law.

Question 16

What are the elements of Ohm’s Law? (AM.I.A.K7)

Answer 16

Voltage(V/E), current (I), and resistance (R) (volts, amps, and ohms).

Question 17

What is the name of the law that describes the relationship in an electrical circuit of voltage, current, and resistance? (AM.I.A.K7a)

Answer 17

Ohm’s Law

Question 18

What is the basic equation of Ohm’s Law? (AM.I.A.K7a)

Answer 18

E = I * R

Question 19

What is Kirchhoff’s voltage law? (AM.I.A.K7b)

Answer 19

Kirchhoff’s voltage law states that the algebraic sum of all voltages around a closed path or loop is zero. Another way of saying it is that the sum of all the voltage drops equals the total source voltage.

Question 20

What is the formula for determining power? (AM.I.A.K7c)

Answer 20

General power formula: P = I * E, where P = power, I = current, E = volts.

Question 21

What is Faraday’s Law? (AM.I.A.K7d)

Answer 21

Faraday’s law, or the law of electromagnetic induction, states that the induced EMF or electromagnetic force in a closed loop of wire is proportional to the rate of change of the magnetic flux through a coil of wire.

Question 22

What is Lenz’s Law? (AM.I.A.K7e)

Answer 22

Lenz’s law states that the EMF induced in an electric circuit always acts in such a direction that the current it drives around a closed circuit produces a magnetic field which opposes the change in magnetic flux.