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Term 1 Theory Prep > Electronics > Flashcards

Electronics Flashcards

1
Q

What is current?

A

The rate of electron flow

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2
Q

What is the unit of measurement for current?

A

Amperes/amps

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3
Q

What is the current of 1 A?

A

1 A = 6.241*10^18 electrons per second

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4
Q

What is charge?

A

The concentration number of electrons at a given circuit point

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5
Q

What is the unit of measurement for charge?

A

Coulombs (C)

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6
Q

What is a conductor?

A

a substance that lets electric charge flow through it

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7
Q

What is an insulator?

A

a substance that offers high resistance to current flow

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8
Q

What is the actual direction of electron flow?

A

a flow of electrons from negative to positive

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9
Q

Are electrons + or - charged?

A

negative

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10
Q

Are protons + or - charged?

A

positive

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11
Q

Are neutrals + or - charged?

A

neutral

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12
Q

What is AC?

A

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

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13
Q

what is DC?

A

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

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14
Q

What are resistors used for?

A

to limit the current in circuits

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15
Q

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

A

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

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16
Q

What is a capacitor?

A

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

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17
Q

What is capacitance?

A

a measurement of the ability of a capacitor to store charge

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18
Q

How does a capacitor store charge?

A

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.

19
Q

What is the formula for calculating resistance in series?

A

RT = R1 + R2 + R3 + R4 +…

20
Q

what is the formula for calculating resistance in parallel

A

1/RT = 1/R1 + 1/R2 + 1/R3 +…

21
Q

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

A

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

22
Q

What are the two types of current?

A

alternating and direct

23
Q

What does the frequency of AC reflect?

A

how many times in a second the current changes direction

24
Q

What is the frequency of DC?

A

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

25
Q

Ohms law

A
26
Q

name examples of conductors

A

silver

copper

gold

aluminium

zinc

nickel

brass

27
Q

name examples of semi-conductors

A

carbon

silicon

germanium

28
Q

Name examples of insulators

A

rubber

plastic

ceramics

air

dry paper

pure water

wood

29
Q

What is resistance? What unit of measurement is used?

A

opposition to current flow

measured in ohms (Ω)

30
Q

What is a semi-conductor?

A

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
31
Q

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

A

AC

32
Q

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

A

DC

33
Q

Define power.

What is the unit of measurement used?

A

DEF: the rate of work done over time or the rate of using energy.

measured in watts (W)

34
Q

Define ‘joule’

A

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

35
Q

How many joules are in 1 Watt?

A

1 W = 1 joule per second

36
Q

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

A

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

37
Q

Capacitance is measured in ________.

A

farads (F)

38
Q

Formula for calculating total capacitance (series)

A

1/CT = 1/C + 1/C2 + 1/C3 + …

39
Q

formula for calculating total capacitance (parallel)

A

CT = C1 + C2 + C3 + …

40
Q

formula for charge, capacitance and voltage

A
41
Q

formula for determining time constant with capacitors (charging time)

A

t = R x C

where t = time

42
Q

voltage is measured in…? What is the symbol?

A

volts (v)

43
Q

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

A

coulombs (

Term 1 Theory Prep (11 decks)

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