Electronics

Question 1

What is current?

Answer 1

The rate of electron flow

Question 2

What is the unit of measurement for current?

Answer 2

Amperes/amps

Question 3

What is the current of 1 A?

Answer 3

1 A = 6.241*10^18 electrons per second

Question 4

What is charge?

Answer 4

The concentration number of electrons at a given circuit point

Question 5

What is the unit of measurement for charge?

Answer 5

Coulombs (C)

Question 6

What is a conductor?

Answer 6

a substance that lets electric charge flow through it

Question 7

What is an insulator?

Answer 7

a substance that offers high resistance to current flow

Question 8

What is the actual direction of electron flow?

Answer 8

a flow of electrons from negative to positive

Question 9

Are electrons + or - charged?

Answer 9

negative

Question 10

Are protons + or - charged?

Answer 10

positive

Question 11

Are neutrals + or - charged?

Answer 11

neutral

Question 12

What is AC?

Answer 12

alternating current changes direction of the current (basically looks like a sound wave–has a positive and negative phase) so electrons are constantly moving in alternating directions

Question 13

what is DC?

Answer 13

Direct current implies electron flow in one direction only, achieved by the supply of a constant voltage.

Question 14

What are resistors used for?

Answer 14

to limit the current in circuits

Question 15

How do you determine the resistance value and tolerance of a 4-band resistor by looking at it?

Answer 15

band 1 = 1st digit band 2 = 2nd digit band 3 = multiplier (1st + 2nd * 3rd) band 4 = tolerance (± x%)

Question 16

What is a capacitor?

Answer 16

a device used to store an electric charge, made of one or more pairs of conductors separated by an insulator (dielectric)

Question 17

What is capacitance?

Answer 17

a measurement of the ability of a capacitor to store charge

Question 18

How does a capacitor store charge?

Answer 18

when connected to an electric circuit one plate attracts electrons and one repels them, leading to a buildup of positive charge on one plate and an equal negative charge on the other.

Question 19

What is the formula for calculating resistance in series?

Answer 19

RT = R1 + R2 + R3 + R4 +…

Question 20

what is the formula for calculating resistance in parallel

Answer 20

1/RT = 1/R1 + 1/R2 + 1/R3 +…

Question 21

What is the direction of conventional current flow? Where is it used and why?

Answer 21

flows positive to negative Used in books and diagrams they were too lazy to change it

Question 22

What are the two types of current?

Answer 22

alternating and direct

Question 23

What does the frequency of AC reflect?

Answer 23

how many times in a second the current changes direction

Question 24

What is the frequency of DC?

Answer 24

does’t have a frequency because it doesn’t change direction

Question 25

Ohms law

Answer 25

Question 26

name examples of conductors

Answer 26

silver copper gold aluminium zinc nickel brass

Question 27

name examples of semi-conductors

Answer 27

carbon silicon germanium

Question 28

Name examples of insulators

Answer 28

rubber plastic ceramics air dry paper pure water wood

Question 29

What is resistance? What unit of measurement is used?

Answer 29

opposition to current flow measured in ohms (Ω)

Question 30

What is a semi-conductor?

Answer 30

a substance that allows current to flow only under specific conditions can have very useful properies like... * allowing current to flow more easily in one direction than the other * showing variable resistance, sensitivity to light or heat

Question 31

What type of current do we use in homes and other buildings?

Answer 31

AC

Question 32

What kind of electricity is used by most of our devices?

Answer 32

DC

Question 33

# Define power. What is the unit of measurement used?

Answer 33

DEF: the rate of work done over time or the rate of using energy. measured in watts (W)

Question 34

Define 'joule'

Answer 34

DEF: the SI unit of work or energy, equal to the work done by a force of one newton when it's point of application moves one meter in the direction of action of the force, equivalent to one 3600th of a watt-hour

Question 35

How many joules are in 1 Watt?

Answer 35

1 W = 1 joule per second

Question 36

What determines the amount of charge that can be held by a capacitor?

Answer 36

size of plates, distance between them and the material used for the dielectric

Question 37

Capacitance is measured in \_\_\_\_\_\_\_\_.

Answer 37

farads (F)

Question 38

Formula for calculating total capacitance (series)

Answer 38

1/CT = 1/C + 1/C2 + 1/C3 + …

Question 39

formula for calculating total capacitance (parallel)

Answer 39

CT = C1 + C2 + C3 + …

Question 40

formula for charge, capacitance and voltage

Answer 40

Question 41

formula for determining time constant with capacitors (charging time)

Answer 41

t = R x C where t = time

Question 42

voltage is measured in...? What is the symbol?

Answer 42

volts (v)

Question 43

charge is measured in what unit? What is the symbol?

Answer 43

coulombs (